Mixed Group

Abstract

The inflammation in dissecting cellulitis and ­folliculitis keloidalis is secondary to follicular rupture and the release of sebaceous and keratinous material and hair keratin fragments. The latter incite an intense inflammatory response. The inflammation is initially neutrophilic and later mixed with lymphocytes, plasma cells, and foreign body giant cells; granulomas may form around the hair keratin fragments. Sinus tract formation is prominent in dissecting cellulitis and rarely found in folliculitis keloidalis. Unlike folliculitis decalvans and tufted folliculitis in which Staphylococcus aureus is usually cultured, in the mixed group, bacterial pathogens are not usually found. Dissecting cellulitis is considered part of the follicular occlusion triad, which includes acne conglobata and hidradenitis suppurativa. The pathogenesis of folliculitis keloidalis is not well understood.