A 35-day-old female came to clinic with a one-day history of two new lesions in her diaper area. The first lesion located near her right labia began 4 days ago and had not changed according to the mother. Last night a second lesion appeared in her left inguinal crease. Initially it was red and swollen but became bluish overtime. The lesions did not appear to cause pain, nor had spreading redness or warmth in this area. Her mother stated that she was otherwise well with no fever orrash and she was feeding, urinating, and stooling well. The mother denied her being around other people that were sick including herself. Her mother denied any open skin lesions nor herpetic ulcers. The past medical history showed a full term infant born by NSVD who went home from the hospital on time. She had been gaining weight well and had been examined for her 1 month check 1 week earlier. The family history was not contributory. The review of systems was negative.
The pertinent physical exam showed of a smiling infant in no distress. Her vital signs were normal including being afebrile. Her growth parameters were 75th to 90th percentile for age. HEENT examination was normal including a flat fontanelle. Her heart, lungs, abdomen, and musculoskeletal examinations were normal. Her genitourinary examination revealed two masses. The first was in the left inguinal crease that was 13 x 7 mm in size. It was purple red in color with no surrounding erythema or edema of the surrounding skin or structures. It was firm but mobile. The second lesion was at the confluence of the right external labia, perineum and leg crease. It was 10 mm x 5 mm with the longitudinal axis oriented parallel with the spine. An area of approximately 5 mm was able to be seen on the perineum that was also purple red in color and there was no surrounding erythema or edema or warmth. From the caudal end, a thread-like structure was possibly palpated. Because of the location and the unusual coloring, the pediatrician considered that these could be abscesses with or without a fistula in the perineal mass or lymph node abscesses. Much less likely was aberrant testes in a phenotypic female or an unusual presentation of a metastatic cancer.
The radiologic evaluation of an ultrasound was performed and confirmed that these masseswere abscesses. The patient was referred to surgery who drained the abscesses of a small amount of purulent material. The patient was placed on amoxicillin-clavulanic acid oral antibiotic. The patient’s clinical course over the next two days showed that the patient remained afebrile and had no obvious discomfort. The abscesses were markedly decreased in size. Laboratory testing at that time showed methicillin-resistant Staphylococcus aureus (MRSA). She was to follow up again in one more week.
Staphylococcus aureus is a gram-positive, catalase-positive coccal bacterium that is found on the skin and respiratory tract. It is the most common cause of skin and soft tissue abscesses. Staphylococcus can also cause enteritis, pneumonia, and toxic shock syndrome. In addition to abscesses, Staphylococcus can cause pustulosis, cellulitis, necrotizing fascitis and other exfoliative skin disease such as bullous impetigo.
Staphylococcus is well-known to colonize the human skin, nail and nares. It is spread by physical contact and aerosolization. Skin breaches allow Staphylococcus to enter the body and to disseminate by hematogenous spread in as little as 1-3 hours. The host immune defenses may clear the bacteremia or Staphylococcus may provoke disseminated disease including sepsis, multiorgan system failure or distant abscesses. Local skin disruption may also cause localized skin disease without bacteremia or dissemination.
To review stages of Staphylococcus abscess formation see To Learn More below.
In the study of afebrile neonates presenting to two emergency rooms with skin and soft tissue infections, 104 infants were evaluated out of > 120,000 emergency department visits. Pustulosis was most common in the genitourinary areas and abscesses were commonly found on the buttocks. All of these patients did not have bacteremia or other serious bacterial infection. When looking at the types of evaluations and treatments the patients received, neonates with abscesses were treated with antibiotics 59% of the time and were admitted to the hospital 55% of the time. Compared to pustulosis and cellulitis, neonates with abscesses had the most variation in evaluation and treatment, as patients with pustolosis generally were less aggressively evaluated and treated and patients with cellulitis were more aggressively evaluated and treated. All patients did well upon discharge.
In another study evaluating methicillin-resistant Staphylococcus in children with superficial genitourinary abscesses, found that MRSA was more common in the groin and external genitalia similar to the patient presented. Their patients ranged in age from 29 days to 17 years with the median age of three years. Young infants were not characterized more specifically. All patients were treated with routine incision and drainage of the abscesses and did well.
There are case reports of neonatal cold abscesses of the large folds of the body caused by Staphylococcus. In 2006, three patients were described that had multiple cold abscesses due to Staphylococcus. The locations were the axillary folds, inguinal folds, supraclavicular fossa, submandibular area, and umbilicus. All of these patients were well, without fever, and had none or very slight surrounding inflammation. All grew MSSA (methicillin sensitive Staphylococcus aureus). All were treated with incision and drainage and antibiotics and did well. The mode of dissemination was unclear but could have been direct invasion of the skin in that location or transitory bacteremia that was controlled by the neonate’s immune system. The patient presented above is similar in that she was a full term infant without any systemic findings and without a specific source of infection. She however had MRSA instead of MSSA.
Questions for Further Discussion
1. What organisms commonly cause cold abscesses?
2. What are indications for an immune evaluation? Click here for more information.
3. What are risk factors for methicillin-resistent Staphylococcal aureus (MRSA)?
- Symptom/Presentation: Mass or Swelling
- Age: Infant
To Learn More
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Huber F, Leaute-Labreze C, Lina G, Sarlangue J, Taieb A, Boralevi F. Multiple neonatal staphylococcal cold abscesses of the large folds. J Eur Acad Dermatol Venereol. 2006 Nov;20(10):1197-200.
Alt AL, Routh JC, Ashley RA, Boyce TG, Kramer SA. Superficial genitourinary abscesses in children: emergence of methicillin resistant Staphylococcus aureus. J Urol. 2008 Oct;180(4):1472-5.
Cheng AG, DeDent AC, Schneewind O, Missiakas D. A play in four acts: Staphylococcus aureus abscess formation. Trends Microbiol. 2011 May;19(5):225-32.
Kharazmi SA, Hirsh DA, Simon HK, Jain S. Management of afebrile neonates with skin and soft tissue infections in the pediatric emergency department. Pediatr Emerg Care. 2012 Oct;28(10):1013-6.
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa Children’s Hospital