Recognizing the skin findings that distinguish pediatric hidradenitis suppurativa

Hidradenitis suppurativa (HS) can be difficult to recognize in children and adolescents, particularly during the early stages of disease when symptoms may resemble more common skin conditions. According to Colleen Cotton, MD, pediatric dermatologists often rely on subtle clinical clues to distinguish HS from infections, cysts, and folliculitis.¹

In a recent interview, Cotton, associate professor of dermatology and pediatrics at George Washington University School of Medicine and Health Sciences and director of the multidisciplinary pediatric HS clinic at Children's National Hospital, discussed the characteristic skin findings that may help pediatricians identify HS earlier and refer patients for specialty care.

Open comedones may provide an early clue

One of the earliest signs of HS may be the presence of open comedones in areas where they would not typically be expected.

"We'll see open comedones in areas where we shouldn't see open comedones," Cotton said. "Typically, we think of comedones as being associated with acne, that's going to be the face, the chest, the back, but if you're seeing what look like blackheads in the underarms, in the groin, on the inner thighs, those are areas we really should not be seeing those, and typically only see them in the context of HS."

Cotton also highlighted the importance of recognizing double-headed comedones, which may represent an early stage of tunnel formation.

"You can also see what are called double-headed comedones, which are like two little blackheads that are connected to each other under the skin," she said. "That's sort of like the earliest, most proto version of a tunnel that we can see."

Recurrent abscesses in skin folds should raise suspicion

Abscesses occurring in intertriginous areas may also signal HS, particularly when lesions recur.

"If you're also seeing somebody who has an abscess in a skin fold and not, you know, in an area outside of a skin fold that should raise your suspicion for HS as well," Cotton said.

She noted that a first episode may be difficult to distinguish from an inflamed epidermal inclusion cyst or infectious abscess. However, recurrence makes infection less likely and should prompt consideration of HS. Cotton recommended obtaining cultures from draining lesions when possible. Growth of methicillin-resistant Staphylococcus aureus may suggest recurrent bacterial infection, whereas mixed organisms, unusual bacteria, or normal skin flora may be more consistent with HS.

Look for evidence of prior disease activity

Even when patients report a first severe flare, examination may reveal signs of previous disease activity.

"Do you see evidence of scarring, do you see post-inflammatory hyperpigmentation in these areas, do you see those open comedones?" Cotton said. "Because if you can see those clues to past disease activity, that can also help you make that diagnosis."

Cotton encouraged clinicians to examine additional affected areas when appropriate.

"If they're coming in for an abscess in the underarm, look at the other underarm," she said. "Look at the groin area, because oftentimes you may see these clues—scarring, post-inflammatory hyperpigmentation, open comedones—in these areas where patients may not recognize that they have them."

Differentiating HS from folliculitis

Folliculitis can be particularly challenging to distinguish from HS because both conditions involve inflammation of hair follicles.

"Folliculitis can also be very difficult to differentiate from HS, because both are follicular disorders and both cause inflammation around the follicles," Cotton said.

According to Cotton, folliculitis tends to be more pustular and may occur in areas such as the lower legs or buttocks. The conditions can overlap, particularly in patients with trisomy 21. Fortunately, mild HS and folliculitis often respond to similar treatments, including antiseptic washes, topical antibiotics, and oral antibiotics during severe flares. Persistent or recurrent lesions despite treatment, however, should raise concern for HS.

For pediatricians, recognizing these characteristic skin findings may help shorten diagnostic delays and improve referral to dermatology before significant scarring and disease progression occur.

Editor's note: This article is part 2 of a 5-part series for Hidradenitis Suppurativa Awareness Week. Throughout the week, Contemporary Pediatrics will feature expert insights on the recognition, diagnosis, and management of HS in children and adolescents. Check back regularly for additional episodes.

Disclosure: Cotton reports no relevant disclosures

References

1. Sabat R, Alavi A, Wolk K, et al. Hidradenitis suppurativa. Lancet. 2025;405(10476):420-438. doi:10.1016/S0140-6736(24)02475-9