Clinical characteristics of pediatric hidradenitis suppurativa: a cross-sectional multicenter study of 140 patients.

Hidradenitis suppurativa (HS) rarely affects pediatric patients. The literature on pediatric HS patients is scarce. This is a cross-sectional study based on case note review or interviews and clinical examination of 140 pediatric patients undergoing secondary or tertiary level care. Patients were predominantly female (75.5%, n = 105) with a median age of 16. 39% reported 1st-degree relative with HS. Median BMI percentile was 88, and 11% were smokers (n = 15). Median modified Sartorius score was 8.5. Notable comorbidities found were acne (32.8%, n = 45), hirsutism (19.3%, n = 27), and pilonidal cysts (16.4%, n = 23). Resorcinol (n = 27) and clindamycin (n = 25) were the most frequently used topical treatments. Patients were treated with tetracycline (n = 32), or oral clindamycin and rifampicin in combination (n = 29). Surgical excision was performed in 18 patients, deroofing in five and incision in seven patients. Obesity seemed to be prominent in the pediatric population and correlated to parent BMI, suggesting a potential for preventive measures for the family. Disease management appeared to be similar to that of adult HS, bearing in mind that the younger the patient, the milder the disease in majority of cases.

Hidradenitis suppurativa (HS): An unrecognized paradoxical effect of biologic agents (BA) used in chronic inflammatory diseases.

BACKGROUND: Paradoxical hidradenitis suppurativa (HS) induced by biologic agents (BA) is scarcely reported. OBJECTIVE: We sought to describe the clinical characteristics and outcome of patients developing paradoxical HS under BA. METHODS: This was a multicenter nationwide retrospective study asking physicians to report all cases of HS, confirmed by a dermatologist, occurring during treatment of an inflammatory disease by a BA. RESULTS: We included 25 patients (15 inflammatory rheumatism, 9 Crohn's disease, 1 psoriasis) treated by 5 BA (adalimumab = 12, infliximab = 6, etanercept = 4, rituximab = 2, tocilizumab = 1). Median duration of BA exposure before HS onset was 12 (range 1-120) months. Patients were mostly Hurley stage I (n = 13) or II (n = 11). Simultaneously to HS or within 1 year, 11 patients developed additional inflammatory diseases, including paradoxical reactions (psoriasis = 9, Crohn's disease = 3, alopecia areata = 1, erythema elevatum diutinum = 1). Complete improvement of HS was more frequently obtained after BA discontinuation or switch (n = 6/10, 60%) rather than maintenance (n = 1/14, 7%). Reintroducing the same BA resulted in HS relapse in 3 of 3 patients. LIMITATIONS: Retrospective nature and lack of complete follow-up for some patients are limitations. CONCLUSION: HS is a rare paradoxical adverse effect of BA, but fortuitous association cannot be excluded in some cases. We observed a trend toward better outcome when the BA was discontinued or switched.

Prevalence of undiagnosed psoriatic arthritis among psoriasis patients: Systematic review and meta-analysis.

BACKGROUND: Skin psoriasis precedes the onset of psoriatic arthritis (PsA) in 84% of patients with psoriasis. Dermatologists have an important role to screen psoriasis patients for PsA. The efficiency of PsA screening remains unknown. OBJECTIVE: We sought to determine the point prevalence of undiagnosed PsA in patients with psoriasis using a systematic search of the literature and meta-analysis. METHODS: PubMed, Cochrane, and Embase database searches yielded 394 studies for review. No study aimed to determine the prevalence of undiagnosed PsA in patients with psoriasis. We assumed that the prevalence of newly diagnosed PsA in patients with psoriasis at the time they seek medical care could be a sound estimate of this value. Seven epidemiological studies and 5 studies on PsA screening questionnaires allowed us to clearly identify patients with newly diagnosed PsA and were selected for review. RESULTS: The prevalence of undiagnosed PsA was 15.5% when all studies were considered and 10.1% when only epidemiological studies were considered. LIMITATIONS: Data were obtained from studies not designed to address the question at hand. Heterogeneity was high (I(2) = 96.86%), and therefore a random effects model was used. CONCLUSION: The high prevalence of undiagnosed PsA in patients with psoriasis adds to the recommendation that dermatologists need to screen all patients with psoriasis for PsA.