Hidradenitis suppurativa is more common than you might think

NEWPORT BEACH, CALIF. – For decades, hidradenitis suppurativa (HS) has been characterized as a rare disorder, but recent evidence from the medical dermatology literature suggests that between 0.4% and 4% of the population is affected, with a predominance in female and black individuals.

At the annual meeting of the Pacific Dermatologic Association, Haley Naik, MD, characterized those estimates as “astounding.” There is also diagnostic delay that ranges from 5 to 14 years in Western populations, said Dr. Naik, of the department of dermatology at the University of California, San Francisco (Br J Dermatol. 2015 Dec;173[6]:1546-9). “These patients are repeatedly interacting with the health care system and they’re not getting the correct diagnosis and therefore they’re not getting effective therapy for the management of their disease,” she said. “We can begin to tackle this problem by educating ourselves and our colleagues about the best ways to diagnose these patients.”

Dr. Haley Naik

In 2015, a group of European researchers published proposed diagnostic criteria for hidradenitis suppurativa (Dermatology. 2015;231[2]:184-90). The criteria comprise three components: typical lesions (double-ended comedones, active inflammatory cysts and nodules, abscesses, follicularly-based papules and pustules, fistula and sinus formation, and scarring); typical distribution (in intertriginous areas such as the axilla and the buttocks), and chronicity (they suggest that patients must have at least two episodes of the disease over a 6-month period). “In addition to satisfying these three criteria, they also suggest that there are some secondary criteria that can be used to help make this diagnosis: a family history of [hidradenitis suppurativa] and absence of pathogens at lesional sites,” Dr. Naik said. “These criteria are a practical framework in which we can begin to educate our colleagues about this diagnosis, but they should not lead us to believe that hidradenitis suppurativa is a phenotypically homogenous disease.”

There are multiple phenotypes of HS, including comedonal, nodular/cystic, and ulcerative. Typical sites that are involved are the axilla, groin, and buttocks. “There is also a subset of patients who are typically thin and male who have a gluteal predominant, or exclusive presentation of their disease,” Dr. Naik said. “In my experience, these patients tend to have severe and progressive disease.” Atypical sites include the postauricular skin, the trunk, and the extremities.

In a cross-sectional study, researchers in France found that HS patients fall into one of three categories. Those in category 1 had involvement of breasts, axilla, and hypertrophic scars; those in category 2 had involvement of the breasts, axilla, ears, chest, back, follicular lesions, and acne, and tended to have a family history of HS; those in category 3 had gluteal involvement with prominent papules and folliculitis (J Invest Dermatol. 2013 Jun;133[6]:1506-11). “Ideally, we hope this type of phenotyping will facilitate phenotype-genotype correlation, and eventually help in understanding disease course of these patients leading to optimized therapeutic options,” Dr. Naik said. “We’re just at the tip of the iceberg here in learning about these various disease subtypes.”

In 2015, the tumor necrosis factor blocker adalimumab (Humira) became the first treatment approved by the Food and Drug Administration for HS, for moderate to severe disease in adults. “The problem is, the dosing and the dose frequency of adalimumab is fixed, so if your patient is only partially responding to the therapy, you don’t have much wiggle room in terms of trying to titrate this medication,” Dr. Naik said. “In that situation the agent of choice to switch to is infliximab.”

Another biologic agent, the interleukin-1 receptor antagonist anakinra (Kineret), also shows promise. Results from a small randomized study of 20 patients found that 7 of 10 patients in the treatment group reported 80% improvement in their disease, compared with 3 out of 10 in the placebo group (JAMA Dermatol. 2016;152[1]:52-9). “Further work needs to be done in this area to understand the efficacy of anakinra for HS,” she said. “I certainly wouldn’t consider anakinra a first- or second-line therapy for the management of HS, but it’s an option for patients who have refractory disease.”

In addition to experiencing fistula and sinus formation, scarring, and wound contractures, HS patients are at risk for developing a host of complications, including lymphedema, peripheral neuropathy, squamous cell carcinoma, chronic pain, anemia, hypoproteinemia, amyloidosis, nephrotic syndrome, and uveitis. According to Dr. Naik, surgical management of HS can be considered in patients who have localized severe disease in which the risks of long-term immunosuppressive therapy outweigh the benefits. “In patients who have chronic refractory disease, surgical management can be particularly helpful,” she said. “In those who have fistula or sinus formation, significant scarring, or range of motion limitation from wound contractures, medical management can only go so far, because the medication can’t really get to those areas.”