Pediatric Dermatology Consult

What is the diagnosis?

A 14-year-old girl with no significant past medical history presents to clinic for evaluation of an abscess. She reports a 1-year history of recurrent painful, draining lesions of the axillae, groin, and buttock, with several lesions occurring each month. She has undergone incision and drainage of her lesions on several occasions, and recently completed a 12-day course of trimethoprim-sulfamethoxazole. The patient reports worsening of her symptoms with heat, sweat, and exercise. Lesions are present at the bilateral axilla and perianal skin.

What's the diagnosis?

Acne conglobata

Epidermal inclusion cysts


Hidradenitis suppurativa

Recurrent MRSA abscesses

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition that is becoming more recognized in children. It has a variable presentation, most commonly presenting as painful, recurrent cysts, abscesses, nodules, and/or pustules in classic locations with associated scarring and sinus tract formation.

The majority of patients present with bilateral lesions found most commonly in the axillae and inguinal folds.1 There are myriad other potential sites of involvement including the inframammary folds, inner thighs, buttocks, and groin.1 Diagnosis is made based on history and physical exam. There is a standard severity classification scheme called the Hurley score, which stratifies disease severity based on the presence of sinus tracts and extent of disease.1 HS is associated with comorbid conditions such as obesity, overweight, acne, and inflammatory bowel and joint disease.2 This painful, persistent condition is well documented to have a negative impact on quality of life in adult patients, and similar impairment has been found in pediatric patients.3,4

Margaret M. Appiah, a pediatric dermatology research associate in the division of pediatric and adolescent dermatology at the University of California, San Diego, and Rady Children's Hospital.

Margaret M. Appiah

HS may be increasing in pediatric and adolescent patients, with recent studies showing onset coinciding most commonly with the onset of puberty.1,2 There is often a period of several years between symptom onset and diagnosis.1 A recent editorial highlighted the disparities that exist in HS, with disease more common in Black children and limited information about disease prevalence in Hispanic children.5

What’s the treatment plan?

HS is a difficult disease to treat, with few patients achieving remission and a significant proportion of patients with treatment-refractory disease.1 There are limited studies of HS treatment in pediatric patients. Topical and systemic antibiotic therapy are mainstays of HS treatment, with tetracyclines and a combination of clindamycin plus rifampin commonly used in adults and children alike. Topical therapies including topical antibiotics and antibacterial solutions are frequently used as adjunctive therapy.6 Adalimumab, a tumor necrosis factor receptor blocker, has been Food and Drug Administration approved for HS for ages 12 and up and is currently the only FDA-approved medication for HS in pediatric patients. Our patient was started on 100 mg doxycycline twice daily, with short-dose topical corticosteroids for symptom management of the most inflamed lesions.

What’s on the differential?

Acne conglobata

Acne conglobata is an uncommon, severe variant of acne vulgaris which arise in patients with a history of acne vulgaris and presents with comedones, cysts, abscesses, and scarring with possible drainage of pus. Lesions can present diffusely on the face, back, and body, including in the axillae, groin, and buttocks, and as such can be confused with HS.7

However, in contrast with HS, patients with acne conglobata will also develop disease in non–apocrine gland–bearing skin. This patient’s lack of preceding acne and restriction of lesions to the axillae, inguinal folds, and buttocks makes acne conglobata less likely.

Dr. Lawrence F. Eichenfield is vice chair of the department of dermatology and professor of dermatology and pediatrics at the University of California, San Diego, and Rady Children's Hospital, San Diego

Dr. Lawrence F. Eichenfield

Epidermal inclusion cyst

Epidermal inclusion cyst (EIC) is a common cutaneous cyst, presenting as a well-circumscribed nodule(s) with a central punctum. If not excised, lesions can sometimes become infected and painful.8 In contrast with HS, EIC presents only uncommonly as multiple lesions arising in different areas, and spontaneous drainage is uncommon. Our patient’s development of multiple draining lesions makes this diagnosis unlikely.


Furunculosis is a common bacterial infection of the skin, presenting with inflammatory nodules or pustules centered around the hair follicle. Lesions may commonly present at sites of skin trauma and are found most frequently on the extremities.9 Though furunculosis lesions may drain pus and can coalesce to form larger “carbuncles,” our patient’s presence of significant scarring and lack of extremity involvement makes HS more likely.

Recurrent MRSA abscesses

Methicillin-resistant Staphylococcus aureus skin and soft-tissue infections are not uncommon in the pediatric population, with presentation of infection ranging from cellulitis to fluid-containing abscesses.10 Recurrent abscesses may be seen in MRSA infection, however in this patient the presence of draining, scarring lesions in multiple locations typical for HS over time is more consistent with a diagnosis of HS.

Dr. Eichenfield is vice chair of the department of dermatology and professor of dermatology and pediatrics at the University of California, San Diego, and Rady Children’s Hospital, San Diego. Ms. Appiah is a pediatric dermatology research associate in the division of pediatric and adolescent dermatology at the University of California, San Diego, and Rady Children’s Hospital. Dr. Eichenfield and Ms. Appiah have no relevant financial disclosures.


1. Liy-Wong C et al. JAMA Dermatol. 2021;157(4):385-91.

2. Choi E et al. J Am Acad Dermatol. 2022;86(1):140-7.

3. Machado MO et al. JAMA Dermatol. 2019;155(8):939-45.

4. McAndrew R et al. J Am Acad Dermatol. 2021;84(3):829-30.

5. Kirby JS and Zaenglein AL. JAMA Dermatol. 2021;157(4):379-80.

6. Alikhan A et al. J Am Acad Dermatol. 2019;81(1):91-101.

7. Greydanus DE et al. Dis Mon. 2021;67(4):101103.

8. Weir CB, St. Hilaire NJ. Epidermal Inclusion Cyst, in “StatPearls.” Treasure Island, Fla: StatPearls Publishing, 2021.

9. Atanaskova N and Tomecki KJ. Dermatol Clin. 2010;28(3):479-87.

10. Papastefan ST et al. J Surg Res. 2019;242:70-7.

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