Recognizing syndromic hidradenitis suppurativa: a review of the literature

Hidradenitis suppurativa (HS) is an inflammatory skin disease causing painful inflammation and suppuration. It may occur in rare syndromes: follicular occlusion, Bazex-Dupré-Christol, Down's, KID, PAPASH, PASS, PASH, and SAPHO syndromes, as well as Dowling-Degos disease. An overview of syndromic HS may inform the search for aetiological factors in HS. PubMed, Ovid and Web of Science were systematically searched using '(hidradenitis OR acne invers*) AND (syndrome OR KID OR PASS OR PAPA OR PASH OR SAPHO OR bazex-dupre OR 'dowling degos' OR triad OR tetrad)' and Cochrane Library using 'hidradenitis OR acne invers*'. A total of 82 articles were included in the final review. We summarize 134 cases collected from the 82 included articles. The syndromes are discussed, focusing on etiopathogenesis, clinical presentation and treatment. This study is based on case reports; therefore, conclusions may be subject to the selection bias. These syndromes are rare; however, it is important to recognize them, as treating them may require a different approach. Three subtypes of syndromic hidradenitis are suggested: syndromes with known genetic abnormalities, syndromes characterized by follicular plugging or structural defects, and syndromes with possible autoinflammatory pathogenesis. There was no universally effective treatment for syndromic HS, and treatment was individualized.

Recent investigations on the relationship between fungal skin diseases and atopic dermatitis

Atopic dermatitis may be associated with chronic dermatophyte infections and Pityrosporum related disorders. Recent epidemiologic studies in school children and young recruits have confirmed that atopic individuals have an increased susceptibility to Trichophyton rubrum infections of the feet and an increased risk for persistent infections. In contrast, an investigation on skin reactivity in dermatophyte infected atopic patients indicated that a group of these patients is fully able to eliminate the fungi concomitant with the development of a delayed type skin reactivity. Facial erythema and scaling, often including neck and shoulders, is present in many young adults with atopic dermatitis. Preliminary data from a Danish-Swedish investigation have shown that atopic dermatitis patients with head-neck-shoulder dermatitis compared to a group without this disorder and normal individuals more often demonstrate positive prick test, RAST and specific histamine release using extract of Pityrosporum ovale. These findings indicate that the presence of Pityrosporum ovale in the skin may cause an allergic reaction leading to dermatitis.