A woman was referred for consultation with painful lesions on her thighs. She was diagnosed with Crohn’s Disease (CD) at age 18 years, and although intestinal symptoms were promptly controlled with azathioprine, perianal involvement remained active. After multiple surgeries in that area, treatment with double-dose infliximab (5 mg/kg every 4 weeks) was initiated and achieved better control of the disease. Five years after starting TNF-α inhibitors, the patient developed painful violaceous inflammatory nodules with scattered follicular papules on her thighs. She was afebrile and did not have diarrhea, abdominal pain, or joint pain. Two biopsies were taken from a nodule. One was sent for histopathologic analysis and the other for tissue culture. Histopathological study revealed a mixed inflammatory infiltrate composed of neutrophils, T and B lymphocytes, and plasma cells distributed around the hair follicles and apocrine glands. The tissue culture tested negative for mycobacteria and fungi and only grew methicillin-sensitive Staphylococcus aureus. Hidradenitis Suppurativa (HS) is a chronic auto-inflammatory skin disease characterized by recurrent, painful, and inflamed nodules, abscesses, and sinus tracts.

It typically affects areas rich in apocrine glands: the axillae, groin, perianal and perineal region, submammary skin, buttocks, and pubic region. With the exception of the medial thigh area, the legs are traditionally thought to be spared by HS. The follicular subtype is characterized by armpit and thigh involvement and the development of nodules. The inflammatory subtype involves the armpits and groin and is characterized by the presence of abscesses and sinus tracts. Therefore, although folliculitis is part of the clinical spectrum of the disease and is especially frequent in the follicular phenotype, cases presenting with a singular feature like painful nodules on the thighs have not been frequently reported, which can complicate their diagnosis. Epidemiologic studies have shown that HS is markedly more common in patients with Inflammatory Bowel Disease (IBD), especially those with CD. Although both diseases share clinical characteristics and risk factors, as well as similarities in their pathogenesis, a clear relationship between both diseases has not been established yet. The use of TNF-α inhibitors to treat these patients could be another risk factor for the development of HS. A recent small case series has described HS as a paradoxical reaction after administration of biologics for other reasons, such as IBD, inflammatory rheumatism, and psoriasis. Adalimumab was the most frequently associated biologic, followed by infliximab, and CD was the most common underlying inflammatory disease. The specific treatment for HS did not change, but complete remission was more frequently achieved when the biologic agent was interrupted or switched. We started our patient’s treatment with oral prednisone and clindamycin and rifampicin. Given the difficulty in controlling the patient’s underlying IBD, we decided to continue treatment with infliximab. The patient’s HS lesions did not progress after her next infusion. Moreover, she did not flare directly with the previous infusions, essentially ruling out the possibility of a paradoxical reaction to the TNF-α inhibitor as an etiology. At follow-up 6 months later, the clinical presentation had improved, with only a few inflammatory nodules present on the thighs that were treated with intraregional corticosteroids.

With Regards,
Sara Giselle
Associate Managing Editor 
Global Journal of Digestive Diseases