What Causes Acute Urticaria?

Patient Presentation
A 4-year-old female came to clinic with a pruritic rash of 1 day duration. She had upper respiratory symptoms for 4 days and the previous evening she began to have a rash on her trunk, upper arms and legs. Her mother described transient lesions, but themselves each appears slightly papular with a lighter center and erythematous base. She had tried a topical steroid without relief. The past medical history was non-contributory. The pertinent physical exam revealed a healthy female with normal vital signs and growth parameters. HEENT showed clear rhinitis and a small amount of fluid in both ears at the bases. Her skin examination had 3-5 mm erythematous macular lesions with a slight papular component centrally. Some seemed to be fading and others progressing. The patient had obviously been scratching areas of the trunk, arms, and legs. The rest of her examination was normal.

The diagnosis of acute urticaria was made. The mother was told that it was most likely due to the upper respiratory tract infection and the natural history was discussed. She was advised to try a diphenhydramine for the pruritis and to return if there were any problems with swallowing or difficulty breathing or if the symptoms did not resolve in a few days.

Urticaria or hives is a systemic disease with cutaneous results. An agent triggers a histamine reaction with cutaneous pruritic lesions being the result. Urticaria usually has intact, erythematous lesions with a papular component that is usually paler in color. Lesions are of various sizes and wax and wane. The lesions may coalesce and blanch with pressure. Scratches and excoriations may be seen. Bullae can be seen in certain circumstances.

Evaluation for systemic reaction is important such as hoarseness, stridor, wheezing, difficulty breathing, arrhythmias, difficulty swallowing or tingling. Acute urticaria is defined as urticaria for less than 6 weeks. Chronic urticaria is defined as wheals that occur at least twice weekly for more than 6 weeks. Because this is a broad definition, some people add that the wheals must be present for more than 1 hour (which distinguishes chronic urticaria from dermatographism) and less than 24-36 hours (which distinguishes it from urticaria-vasculitis). The maintstays of treatment are antihistamines, short-acting ones for acute urticaria and long-acting ones for chronic urticaria.

Mastocytosis or angioedema may appear similar to urticaria but are different. Angioedema frequently occurs in mucous membranes and may or may not have urticarial wheals present. Mastocytosis is a heterogeneous group of mast cell disorders which may cause wheal-like lesions on the skin.

Learning Point
The most common cause of acute urticaria is respiratory viral infections.

The differential diagnosis of acute urticaria includes:

  • Blood products
  • Contact/Topical exposure – soaps, lotions, detergents
  • Drugs – many including antibiotics, ACE inhibitors, NSAIDS, opiates, radiocontrast, components of biological agents, preservatives
  • Food – peanuts, tree nuts, eggs, milk, shellfish, strawberries, chocolate, etc.
  • Dyes and preservatives
  • Environmental and inhalant
  • Idiopathic
  • Insect bites
  • Infections – hepatitis, Epstein-Barr virus, upper respiratory tract infections, Streptococcus
  • Physical – dermographism, cold, cholinergic, heat or solar, aquagenic

Questions for Further Discussion
1. What are indications for evaluation by an allergist?
2. What are indications for prescribing prophylactic epinephrine (i.e. Epi-Pen®)?

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: Hives.
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.

Illingworth RS. Common Symptoms of Disease in Children. Blackwell Scientific Publications: Oxford. 1988:352.

Fleisher GR, Ludwig S. Synopsis of Pediatric Emergency Medicine. Williams and Wilkins. Baltimore, MD. 1996:221.

Leech S, Grattan C, Lloyd K, Deacock S, Williams L, Langford A, Warner J; Science and Research Department, Royal College of Paediatrics and Child Health.The RCPCH care pathway for children with urticaria, angio-oedema or mastocytosis: an evidence and consensus based national approach. The RCPCH care pathway for children with urticaria, angio-oedema or mastocytosis: an evidence and consensus based national approach. Arch Dis Child. 2011 Nov;96 Suppl 2:i34-7.

Marrouche N, Grattan C. Childhood urticaria. Curr Opin Allergy Clin Immunol. 2012 Oct;12(5):485-90.

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    8. Health care services aimed at preventing health problems or maintaining health are provided.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.


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