What Causes Hyperkalemia?

Patient Presentation
A 7-year-old male came to the emergency room with swelling and pain of his right arm. He was known to have chronic renal insufficiency secondary to prune belly syndrome. He was receiving hemodialysis three times weekly and had already had several catheter replacements because of thrombosis and sepsis in the past. The swelling of the upper inner arm began about 12 hours previously and was overlying his current catheter site. Since that time he had increased swelling of the area and forearm. He also had increased pain. He had no fever, chills, emesis, diarrhea, rashes, or cough and he denied any obvious trauma. His last dialysis was 6 days ago because he had missed a session due to his poor social situation. He denied any palpitations, muscle weakness or tetany. The past medical history of thrombosis of catheters, sepsis, and electrolyte abnormalities because of missing medication. He had chronic anemia, short stature, and chronic lung disease additionally. The social history showed that the family was non-compliant with medications and had missed 3 dialysis appointments in the past, but never two treatments in a row though.

The pertinent physical exam showed a short male with obvious swelling of his upper right arm overlying his catheter site. His blood pressure was 138/82, pulse 98, respiratory rate of 24 and he was afebrile. His weight was 4 kilos above his dry weight. Pulsations in the catheter could not be felt and muffled sounds were heard at the ends of the catheter on auscultation. There was some mild redness and warmth but mainly it appeared swollen. There was no obvious trauma to the extremity. His heart was regular rate and rhythm without murmurs. His abdomen was soft without much musculature.

The diagnosis of probable hemodialysis catheter malfunction was made and confirmed by fluoroscopy. The laboratory evaluation showed numerous electrolyte abnormalities including his potassium at 7.6 mEq/L. An ECG showed mild elevation of his T waves. He was admitted to the Pediatric Intensive Care Unit for chronic renal insufficiency, hyperkalemia and electrolyte abnormalities, catheter thrombosis, hypertension and fluid overload. He was treated with a calcium infusion, salbutamol nebulizer and glucose and insulin infusion initially. He also was started on sodium bicarbonate later which improved his potassium to 5.9 mEq/L over several hours. After seeing stabilization of his potassium, he was taken to the operating room and a new catheter placed. Hemodialysis could be restarted soon after which helped to also stabilize his overall condition, including normalization of his potassium and other electrolyte abnormalities. Before discharge, social services and the dialysis team made a new contract with the immediate and extended family with plans for intervention if the patient failed to come for his hemodialysis appointments. He was then discharged to home.

Potassium (K+) is an alkali metal (Group 1 of periodic table with Hydrogen, Lithium and Sodium) with an anatomic number of 19. Its chemical symbol K, comes from the medieval Latin, kalium which means potash (mainly potassium carbonate or potassium hydroxide), the substance it was first isolated from.

Potassium is an important cation and it mainly resides in the intracellular fluid with only a small amount in the extracellular fluid. Potassium regulates cell volume, pH and enzyme functions. Hyperkalemia is defined as a potassium level > 5.5 mEq/L in children and > 6.0 mEq/L in newborns.

Hyperkalemia increases cellular membrane excitability and can cause significant problems with the myocardium, resulting in potentially lethal dysrhythmias. The problem is that hyperkalemia can be completely asymptomatic for the patient and even on ECG. First ECG changes are peaked T waves occurring around > 5.6 mEq/L. With increased K+ levels, the PR interval prolongs and the QRS complex becomes widened. Physical symptoms due to hyperkalemia include muscle weakness, reduced deep tendon reflexes, and paresthesias. Symptoms of the underlying disease obviously also occur.

Hyperkalemia is a medial emergency because of its cardiac problems. Treatment is started if there is electrocardiographic changes or serum K+ > 6.0-6.5 mEq/L. K+ levels > 6.0 mEq/L are common in neonates and young children due to pseudohypokalemia (i.e. hemolysis caused by venipuncture or capillary sampling) and a free-flowing blood sample should be re-evaluated if pseudohypokalemia is suspected.

Treatment of the underlying disease process is the most important. Reviewing other causes such as drugs or intravenous fluids which may increase the K+ is also important. Acute management is usually centered on changing the equilibrium quickly to move K+ intracellularly and to stabilize the myocardium. This buys time until other treatments can be implemented or can take effect.

If hyperkalemia is diagnosed, an ECG should be done along with other laboratory testing for underlying causes of hyperkalemia including a complete blood count, complete metabolic panel, glucose and glycosylated hemoglobin, lactic dehydrogenase, uric acid, creatine kinase, urine for blood, hemoglobin and ketones, and others such as renin, angiotensin, aldosterone, cortisol, 21-hydroxylase, 17-OH progesterone and 11-beta-hydroxylase.

A review of hypokalemia can be found here.

Learning Point
The differential diagnosis of hyperkalemia and treatments includes:

  • Increased input
    • K+ supplements – oral or intravenous
    • Sodium substitutes – are often K+ based
    • Increased K+ rich foods – bananas, potatoes, beans, grains
    • Blood transfusion
    • Leukocytosis or thrombocytosis
    • Treatment: Decrease input
      • Stop any K+ containing intravenous fluids or oral supplements
      • Use fresh or washed blood for transfusion
  • Redistribution of K+ to extracellular space
    • Pseudohypokalemia – very common in children due to sample hemolysis
    • Drugs – beta blockers,
    • Exercise, strenuous
    • Hyperkalemic periodic paralysis
    • Insulin deficiency – diabetic ketoacidosis
    • Intravascular hypoosmolality
    • Intravascular volume depletion
    • Metabolic acidosis
    • Tissue breakdown
      • Chemotherapy and tumor lysis syndrome
      • Hemolysis
      • Hyperthermia
      • Rhabdomyolysis
      • Sepsis
      • Trauma and burns
    • Treatment: K+ redistribution to intracellular space
      • Calcium infusion
          This stabilizes the cellular membrane and increases the membrane resting potential (hyperkalemia does the opposite). 10% calcium gluconate, 0.5 ml/kg or 0.11 mmol/kg given by slow IV infusion over 5-10 minutes. Effects last 30-60 minutes only.
      • Insulin and Glucose infusion
          Insulin drives K+ intracellularly by exchanging Na+ extracellularly.
          Glucose infusions increase endogenous insulin secretion. “Insulin infusion will only need to be started when blood glucose is over 10 mmol/l.” Glucose infusion may be enough.
          Insulin can be infused at 0.1-0.6 units/kg/hour in neonates, or 0.05-0.2 units/kg/hour for > 1 month olds, ALONG WITH, a glucose infusion of 0.5-1 g/kg/hour (= 5-10 ml/kg/h of 10% glucose). Onset of action is ~15 minutes and can last for hours but glucose needs to be monitored closely as hypo- and hyper-glycemia can occur.
      • Sodium bicarbonate
          Metabolic alkalosis causes hydrogen ions to move extracellularly, with K+ moving intracellularly to compensate.
          Sodium bicarbonate 1 mmol/kg over 10-15 minutes OR correct half of the base excess (0.3 x weight x BE). Action onset is about 1 hour and can last for 2 hours. This can cause other electrolyte abnormalities such as hypernatremia and hypocalcemia.
      • Beta-adrenergic agonists
          Beta agonists increase cellular membrane activity and drive K+ intracellularly in exchange for Na+ moving extracellularly. Nebulized or intravenous salbutamol are the most commonly used. Onset is quick with effects lasting up to 2 hours. Dosing can be repeated as needed and tachycardia is the main side effect.
  • Decreased output
    • Acute/chronic renal disease
    • Dialysis, inadequate or missed treatment
    • Decrease arterial blood flow
    • Hypoaldosteronism
      • Congenital adrenal hyperplasia
      • Aldosterone synthase deficiency
    • Aldosterone resistance
      • Pseudohypoaldosteronism
      • Distal renal tubular acidosis (Type IV)
        • Sickle cell anemia
        • Urinary tract obstruction/reflux
      • Drugs
        • ACE inhibitors
        • Cyclosporin
        • K+ sparing diuretic
        • Non-steroidal anti-inflammatory drugs
    • Treatment: Increase Output
      • Loop diuretics
          Work by directly increasing urinary K+ excretion and decreasing resorption of K+ and Na+. It is helpful for hyperkalemia due to congestive heart failure or hypoaldosteronism. Furosemide 1 mg/kg intravenously over 5 minutes can be given. Avoid rapid administration. Patients with renal failure may need additional dosing.
      • Cation exchange resins
          They bind potassium in exchange for calcium in the gut. It can be given orally or rectally but doesn’t taste very good and the K+ exchange occurs slowly over 1-2 hours. It can also cause electrolyte abnormalities and should be used with caution especially in very young children. It can remove 0.5-1 mmol of K+ for each gram of resin. Dosing depends on age and administration site.
      • Dialysis
          Is used often when other methods of removal fail however the K+ reduction is seen almost immediately and can be sustained for long periods of time. Hemo- or peritoneal dialysis can be used.

Questions for Further Discussion
1. What is prune belly syndrome and how is it diagnosed?
2. What is the life span of patients with prune belly syndrome?
3. What are indications for social service intervention in patients with chronic disease?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for this topic: Potassium

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Rudolph CD, et.al. Rudolph’s Pediatrics. 21st edit. McGraw-Hill, New York, NY. 2003:1653-1654.

Masilamani K, van der Voort J. The management of acute hyperkalaemia in neonates and children. Arch Dis Child. 2012 Apr;97(4):376-80.

Hollander R, Mortier G, van Hoeck K. Hyperkalemia in young children: blood pressure checked? Eur J Pediatr. 2016 Dec;175(12):2011-2013.

Fordjour KN, Walton T, Doran JJ. Management of hyperkalemia in hospitalized patients. Am J Med Sci. 2014 Feb;347(2):93-100.

Potassium. Wikipedia. Available from the Internet at https://en.wikipedia.org/wiki/Potassium (rev. 6/8/18, cited 7/6/18).

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

What Type of Conservative Treatments Can Help for Plantar Fasciitis?

Patient Presentation
A 12-year-old female came to clinic with a 2-3 week history of right heel pain. She had started running about 1 month ago and had slowly increasing heel pain since then. She said the pain was worse after running and when initially getting up in the morning. Recently she also noticed that it was painful after she was sitting for a period of time. After getting up and moving though the pain got better. Her mother was worried because she was limping first thing in the morning. The patient had purchased new shoes for running and was running on concrete sidewalks. They had not tried stretching, antipyretics or ice for pain relief. The past medical history was non-contributory.

The pertinent physical exam showed a happy individual in no distress. Her vital signs were normal and she was not overweight. She had full range of motion in her ankle, forefoot and toes, but had less bilateral flexibility when her Achilles tendons were stretched. Pain could not be elicited by palpation or forefoot extension while seated. However, when standing the patient pointed to medial heel pain with standing that increased with forefoot extension. She had no pain at the Achilles insertion. No pain could be elicited in any other areas of the foot.

The diagnosis of plantar fasciitis was made. The pediatrician looked at her shoes and did not see excessive wear or an abnormal wear pattern. She recommended that the girl make sure to warm up well before running and to run on softer terrain. “You can also get a heel cup to give a little more support when you are running,” she advised. “I’ll also show you a couple of stretches that you can do to help stretch the shock absorber in your foot called the plantar fascia,” she explained. “Good support, stretching and ice, over a few weeks usually helps people a lot,” she explained.

The plantar fascia consists of 3 bands of dense connective tissue that originates in the medical calcaneal tubercle and inserts into the base of each of the 5 proximal phalyanxes in a fan-shaped distribution. It acts as a shock absorber and reinforces the medial longitudinal arch as the foot undergoes forward propulsion. The -itis in plantar fasciitis (PF) is a misnomer as it is not an acute inflammation but is a chronic degenerative process involving the plantar fascia aponeurosis of the foot usually at the medial tubercle of the calcaneous. Repetitive strain seems to cause microtearing which then causes a repair response where there can be thickening and fibrosis of the plantar fascia. Plantar fasciosis is a more accurate term to describe the pathology as it is currently understood.

About 1 million visits occur each year for PF in the US. It is most common in the 45-64 year old age group and least common in the pediatric age group. However it does occur as a chronic overuse syndrome for pediatric patients particularly those that are deconditioned, starting new exercise regimens, exercising on a hard surface or are obese. These are risk factors for all age groups and other risk factors include standing for long time periods, sedentary individuals, military personnel or long-distance runners. Additional risk factors include pes planus, pes cavus, shortened Achilles tendon, limited ankle dorsiflexion, weak foot or plantar flexor muscles, and overpronation. Environmental risk factors include deconditioning, working/exercising on a hard surface, prolonged weight bearing, walking barefoot, poor footwear, and inadequate stretching. Females may or may not be at increased risk.

The differential diagnosis includes posterior tibial nerve impingement (tarsal tunnel syndrome that has paraesthesa with dorsiflexion), fascial rupture, calcaneal fractures, calcaneal apophysitis (a review can be found here), Achilles tendonitis, arthritis, bursitis or fat pad contusion.

Diagnosis is usually clinical with a history that classically includes medial heal pain with first steps in the morning that improves with movement throughout the day or improves with rest. This scenario may repeat itself after sitting for a prolonged period. The pain is worsened after long periods of standing or over the course of the day with excessive movement. The pain is reproducible with dorisflexion of the foot.

Learning Point
PF treatment is usually conservative but it can take a long time. Fortunately 85-90% of patients have successful treatment. It is estimated that the stretching routines must be done for at least 1/2 of the time that the patient has had symptoms to have relief or at least ~6-8 weeks.

Conservative treatment includes:

  • Using good footwear with arch and heel cushioning- not walking barefooted or in sandals
  • Over the counter orthotics – heel or full-foot premade orthotics can provide additional arch and heel cushioning and support.
  • Rest and modification of activities
  • Use a thick mat if patient has to stand for a long time in one area
  • Stretching of foot, ankle and calves as a treatment and in general before exercise
  • Massage
  • Pain control – Ice and/or anti-pyretics / non-steroid anti-inflammatory drugs
  • Weight loss

Additional treatments after usually 6-8 weeks can include:

  • Physical therapy
  • Corticosteroid injection (has a 10% risk of plantar fascial rupture)
  • Anterior night splint
  • Other treatments can include extracorporal shock wave therapy or ultrasound therapy, osteopathic manipulative therapy

If still no improvement after an additional 6-8 weeks:

  • Orthopaedic consultation
  • Fasciotomy

Stretching before first steps in the morning or after sitting for a period of time can really help. Stretching is the best treatment.
Stretching daily can include:

  • Calf and ankle stretches – a towel is wrapped around the ball of the foot and then dorsiflexed. Each stretch is 30 seconds. Rest 30 seconds in between. Do each stretch 3 times. Do this 2-3 times/day.
  • Plantar fascial stretch – ankle and foot are dorsiflex and all toes are gently extended with the hand. The plantar area is massaged with the other hand. Each stretch is 30 seconds. Rest 60 seconds in between. Do each stretch 3 times. Do this 2-3 times/day.
  • Rolling plantar fascia – roll a ball, small can, or frozen water bottle back and forth. Roll for 60 seconds. Rest 30 seconds in between. Do each stretch 2-3 times/day.
  • Towel pick up – a paper towel is picked up and dropped by the toes. Do this for 120 seconds once a day.
  • Wall push – with the ball of the foot on the base of a wall and the heel on the ground, the patient leans into the wall. Each stretch is 10 seconds. Rest 10 seconds in between. Do each stretch for 2 minutes at least 2 times a day or even every hour.
  • Achilles tendon stretch – while standing on step, drop heel off the back of the step, keeping knees straight and also repeat with knee slightly bent. Each stretch is 30 seconds. Rest 30 seconds in between. Do each stretch 3 times. Do this 2-3 times/day.

Questions for Further Discussion
1. How common is plantar fasciitis in cultures who use less footwear?
2. What are indications for imaging with plantar fasciitis?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Heel Injuries and Disorders

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

American Physical Therapy Association. Physical Therapist’s Guide to Plantar Fasciitis. Available from the Internet at https://www.moveforwardpt.com/SymptomsConditionsDetail.aspx?cid=a2395ee9-08bb-47cc-9edc-1943e2fdbf2e
(rev. 8/28/11, cited 7/3/18).

Schwartz EN, Su J. Plantar fasciitis: a concise review. Perm J. 2014 Winter;18(1):e105-7.

Thompson JV, Saini SS, Reb CW, Daniel JN. Diagnosis and management of plantar fasciitis. J Am Osteopath Assoc. 2014 Dec;114(12):900-6.

Pollack A, Britt H. Plantar fasciitis in Australian general practice. Aust Fam Physician. 2015 Mar;44(3):90-1.

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

What Should Be In A Mental Health Safety Plan?

Patient Presentation
In the early fall, several residents were discussing an increase in admissions for suicide attempts to the hospital. “Starting school sure is stressful for some kids. Lots of classroom stress, boyfriend/girlfriend stress, and all the other social stress. Luckily, one took pills and then called someone to tell them about it and she got to the hospital right away. The other one, the mother noticed that he had been cutting his forearms and she brought him to the emergency room before he did something else,” one resident recounted. “Since I’ve been working in the ER this month, we’ve been doing a lot more depression and suicide screening and I’ve gotten better at making safety plans with families,” another resident said. “What do you do when you make a safety plan? I haven’t done that. Usually the psychiatry resident or nurse does that on the inpatient floor,” an intern asked. “Usually there is a nurse in the ER who also does it, but I’ve done a couple. We have a form we fill out in the ER with the patient and family. I’ll show you,” said the ER resident.

IF YOU ARE IN A CRISIS SITUATION AND NEED HELP, call 1(800) 273-TALK(8255) there IS someone there who can help you, En Espanol 1-888-628-9454, or Text “HOME” to 741-741 .
Other resources are available at http://www.suicidepreventionlifeline.org

About 10-20% of children and adolescents have a mental health or substance abuse disorder. Suicide is the seconding leading cause of death in the US for ages 10-19 years old at ~2000/year. Unfortunately the numbers of trained mental health professionals in the US and most countries is inadequate to provide appropriate care.

Emergency department (ED) visits for psychiatric conditions increased from 4.4% to 7.2% in 2011 and most likely is higher currently, as the emergency room is used to access mental health services that often are weeks to months away for an outpatient appointment. Most of the ED visits are for adolescents and volume varies according to the school year and calendar; stressful times such as beginning and ending of terms, final examinations or national examinations may be reasons for increased visits. “According to the results of the 2013 National Youth Risk Behavior Survey, 17% …of high school students reported having “seriously considered attempting suicide” during the [past] 12 months…,” 14% reported making a suicide plan, and 8% reported a suicide attempt.

Asking about suicide or screening for suicide does not increase attempts, but in a study, screening allowed pediatric patients “”…to feel known, heard and understood,” by an unbiased listener.” Suicide risk assessment tools for pediatric patients can be reviewed here.

  • Reynolds Suicide Ideation Questionnaire – a standard self-administered questionnaire that takes about 10 minutes to complete, but it is recommended that providers have training using the instruments.
    Information can be found from several online publishers.

  • Columbia Suicide Severity Rating Scale – a semi-structured interview that takes variable amounts of time depending on the answers. Providers need training but online training is available.
    Information is available through the Columbia Lighthouse Project here.

  • Ask Suicide-Screening Questions – 4 item questionnaire that takes 2 minutes to administer. All answers are Yes or No. Forms and instructions are available through the National Institute of Mental Health here

      1. In the past few weeks, have you wished you were dead?
      2. In the past few weeks, have you felt that you or your family would be better off if you were dead?
      3. In the past week, have you been having thoughts about killing yourself?
      4. Have you ever tried to kill yourself? If yes, how and when?

      If YES, to any of Questions 1-4 ask:
      5. Are you having thoughts of killing yourself right now?


        If answers to Questions 1-4 are all NO, then screening is complete and no intervention is needed.

        If any answer to Questions 1-4 is YES, then ask question 5.

        If NO to Question 5, this is considered a non-acute positive screening because a potential risk is identified. The patient requires a brief suicide safety assessment to determine if a full mental health evaluation is needed. The patient cannot leave the office/ED without being evaluated for safety. Appropriate personnel should be contacted immediately.

        If YES to Question 5, this is an acute positive screening with imminent risk identified. The patient requires an immediate (STAT) full mental health evaluation and safety evaluation. The patient cannot leave until evaluated for safety. The room the patient is in should be made safe by removing dangerous objects, and the patient should be kept in sight. Appropriate personnel should be contacted immediately.

To review a case about post traumatic stress disorder in children click here
To review a case about resiliency to the effects of war click here.

To review a case about the effects of bullying click here.

To review a case about gun violence click here.

Learning Point
Treatment for suicidal ideation and attempts is multi-modal with medication, psychotherapy and appropriate support from health professionals, family, and friends. The appropriate environment must be chosen at various points in treatment to protect the patient’s safety. In community/home settings items that could be used for deliberate self-harm should be removed including weapons, sharp instruments, and medications, and the patient should be monitored frequently. Locations within the community/home where patients could be more likely to deliberately hurt themselves should be identified and also monitored frequently such as a balcony, window, stairs, pools and other bodies of water, etc.

A mental health safety plan is a tool that helps the patient to identify resources they can use if the suicidal urge occurs again. Patients can list their coping strategies after each element.
Elements include:

    List: The one thing that is most important for the patient and worth living is:
    1. Recognizing warning signs: Warning signs that a crisis may be developing such as thoughts, images, mood, situation, behaviors
    2. Internal coping strategies: Things that the patient can do to take their mind off problems without contacting another person such as relaxation techniques, physical activity, etc.
    3. Socialization strategies for distraction and support: People and social settings that provide distraction or support – names or places, telephone
    4. Social contact for assistance in resolving crisis: People the patient can ask for help – names and telephone
    5. Professionals or agencies contacts to help resolve crisis: Professionals or agencies the patient can contact during a crisis – clinician name/location/phone/emergency contact number, local urgent care services with address/phone, Suicide Prevention Lifeline Phone
    1(800) 273-TALK(8255), En Espanol 1-888-628-9454, or Text “HOME” to 741-741
    6. Means restriction: Ways to make the environment safe

Questions for Further Discussion
1. What are risk factors for depression and/or suicide?
2. What are medical treatment options for acute and chronic treatment of depression and/or suicide?
3. What local resources do you have for patients who may be in crisis?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for these topics: Suicide, Teen Depression and Self Harm.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

US Department of Veterans Affairs. VA Suicide Prevention Resources. Safety Planning. Available from the Internet at:
https://starttheconversation.veteranscrisisline.net/pdf/what-is-a-safety-plan/ (cited 6/29/18).

Sher L, LaBode V. Teaching health care professionals about suicide safety planning. Psychiatr Danub. 2011 Dec;23(4):396-7.

Norris D, Clark MS. Evaluation and treatment of the suicidal patient. Am Fam Physician. 2012 Mar 15;85(6):602-5.

Carubia B, Becker A, Levine BH. Child Psychiatric Emergencies: Updates on Trends, Clinical Care, and Practice Challenges. Curr Psychiatry Rep. 2016 Apr;18(4):41.

ASQ Suicide Risk Screening Questionnaire. National Institute of Mental Health. Available from the Internet at: Page (rev 6/13/17, cited 6/29/18)

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

What Are Common Cross-reactivities with Other Allergens?

Patient Presentation
A 3-month old came to clinic for blood in his stools. He was breastfeeding and his mother had already stopped using dairy products in her diet. He was now having obvious blood for the last 2-3 stools. He was otherwise acting well and had no changes to his skin or problems swallowing or breathing, The past medical history was positive for previous blood in his stools around 3-4 weeks of age. He also had mild infantile atopic dermatitis that was controlled with emollients. The family history was positive for an older sibling with allergy to cow’s milk protein and soy causing gastrointestinal symptoms. His father also had asthma and a tree nut allergy where he had orpharyngeal swelling and wheezing. His father carried epinephrine with him for his allergies. The review of systems was otherwise negative.

The pertinent physical exam showed a healthy infant with normal vital signs and growth parameters in the 25-75%. His skin was slightly dry on his face, trunk and legs, but not with significant inflammation. HEENT, lungs, heart and abdomen were negative. His anus had a small amount of obvious blood around it that tested positive for blood.

The diagnosis of increasing problems with probable cow’s milk protein allergy was made. The mother was well-educated about the problem and after discussion about potential options wanted to stop breastfeeding and use a formula. “I don’t want to stop breastfeeding but I think it will be the clearest option to make sure he doesn’t get more cow’s milk by accident,” she stated. “The recommendations are to use an elemental formula which I would highly recommend in your family, especially as his brother already has a soy allergy,” the pediatrician stated. “I’d also like to see a pediatric allergist. There’s just so many allergies in the family and I’d like to talk with them and their nurses directly. I think I would feel better about what I can do to continue to avoid the foods and what to do if things get worse. We don’t have a problem with peanuts but what if that happens too,” the mother requested. The pediatrician agreed with the consultation and referred the family.

The most common allergic foods are cow’s milk (most common), egg, peanut, tree nut, soy, wheat, fish and shellfish. Egg, milk, soy and wheat tend to occur in young children and these are more likely to be outgrown over time. Peanut, tree nut, shellfish, and fish occur at all ages and are less likely to be outgrown. Peanut and tree nut allergies also tend to be more severe than other foods. Ninety percent of food fatalities were attributed to tree nuts and peanuts. In a study of anaphylaxis in schools, food was the most likely trigger (54%) with nuts and fruits being the most commonly identified foods. Co-factors of food-induced anaphylaxis include asthma, exercise, non-steroidal anti-inflammatory drugs, infections and alcohol.

Treatment for food allergy is strict avoidance of the food(s), management and avoidance of potential co-factors, and immediate management of reactions. Immunotherapy is one option for some allergens and a review of its indications can be found here.

Cross-reactivities within a plant group are common. For example the Rosacae family has many agriculturally important trees and plants and cross-reactivities between the them is common. Cross-reactivity syndromes do occur. Oral allergy syndrome or pollen food allergy syndrome is caused by shared homology between pollens, fruits, vegetables and tree nuts. Patients usually are sensitized to an environmental pollen and then have reactions with oral ingestion of various foods. Symptoms are usually localized to the oropharynx (i.e. tinging, itching, mild swelling). Systemic reactions are less common and anaphylaxis is rare. Latex fruit syndrome is again caused by shared homology. People who are allergic to latex may have reactions include apples, avocado, chestnuts, banana, kiwi, tomato, bell pepper and carrot. Ficus trees have some cross-reactivity too. Reactions can be severe. A review of latex allergy can be found here.

Learning Point
Common allergens and their cross-reactivities with other allergens are listed below.
Note: The examples given are common but not necessarily a comprehensive listing of all cross-reactivities.


Allergen How Common Overall? Cross-reacts with (examples) Avoidance Pattern Other
Cow’s Milk Most common food allergy – 2.0 – 3.5% for children, 1.94% in adults Goat’s milk – 92%, Cooked beef – 10%, Soy 14-70% Cow’s milk can be avoided, Cooked beef is recommended not to be avoided Often outgrown as child ages, Baked/cooked milk is often tolerated
Egg 1.3 – 3.2% in children and 0.51% in adults Egg can be avoided Often outgrown as child ages, Some proteins are less allergenic if cooked/baked, Influenza vaccine is recommended for those with documented egg allergy
Peanut 0.6 – 1.3% in children 5% between legumes (ex. peas, lentils, beans and soy), Peanut cross-reactivity is unknown, but within atopic individuals is reported as between 23-50% All peanuts should be avoided, Soy can be avoided Tends not to be outgrown, Fatal reactions are more common, Roasting peanuts can increase allergenicity
Tree nuts 0.2 – 0.5% in children and 0.87% in adults 37% within the tree nuts (ex. almond, brazil nuts, cashew, almond, hazelnut, pecan, pistachio, etc.), Peanut cross-reactivity is unknown, but within atopic individuals is reported as between 23-50% Avoid tree nuts, see notes about cross-reactivity with peanuts above or to left Fatal reactions are more common
Wheat 20% between grains (ex. barley, rye) Avoid only the wheat, not other grains unless specific testing shows reactions Often develops in childhood and then outgrown by adulthood
Shellfish 0.87% in children and 2.04% in adults Cross-reactivity within shellfish is 75%. Occurs in different crustaceans and also insects such as cockroach, dust mite and grasshopper Avoid all shellfish, There is not specific cross-reactivity between shellfish and fish, There is not specific cross-reactivity with iodine allergy or radiocontrast reactions. Usually develops during childhood and not outgrown
Fish 0.4 – 0.6% in children Cross-reactivity between fish is 50% (ex. swordfish, sole), There is not specific cross-reactivity between shellfish and fish Avoid all fish unless specific food testing shows tolerance for specific fish type
Pollen (Birch, Ragweed, etc.) 55% with other fruits/vegetables (ex. apple, peaches, honeydew) Ragweed often cross-reacts with bananas, melons, cucumbers and tomatoes, Grasses cross-react with kiwi, melons, peaches and tomato
Peach 55% with other Rosacae family such as apple, plum, cherry, pear Avoid specific fruits
Melon 92% with other fruits, avocado, banana, watermelon Avoid specific fruits
Latex Fruits, avocado, banana, kiwi If allergic to latex fruits are 35% cross-reactivity, if allergic to the fruit, the cross-reactivity to latex is 11%, avoid specific fruits

Questions for Further Discussion
1. What are recipes for introducing peanut foods for potentially high-risk infants? A review can be found here.
2. What proteins cause cow’s milk protein allergy? A review can be found here.

Related Cases

    Symptom/Presentation: Bloody Stool

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for this topic: Food Allergy

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Host A, Halken S. Cow’s milk allergy: where have we come from and where are we going? Endocr Metab Immune Disord Drug Targets. 2014 Mar;14(1):2-8.

Isok S, Arıkan-Ayyıldız Z, Caglayan-Sozmen S, Fırıncı F, Tuncel T, Karaman O, Uzuner N. Cross-reactivity syndromes: presentation of two cases and review of the literature. Turk J Pediatr. 2014 May-Jun;56(3):291-4.

Patel BY, Volcheck GW. Food Allergy: Common Causes, Diagnosis, and Treatment. Mayo Clin Proc. 2015 Oct;90(10):1411-9. doi: 10.1016/j.mayocp.2015.07.012.

Radlovic N, Lekovic Z, Radlovic V, Simic D, Ristic D, Vuletic B. Food allergy in children. Srp Arh Celok Lek. 2016 Jan-Feb;144(1-2):99-103.

White MV, Silvia S, Muniz R, Herrem C, Hogue SL.
Prevalence and triggers of anaphylactic events in schools. Allergy Asthma Proc. 2017 Jul 1;38(4):286-293.

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa