Alternaria scalp infection in a patient with alopecia areata. Coexistence or causative relationship?

Abstract

Background: Alopecia areata is an autoimmune disease that is affecting anagen hair follicles. The triggers of autoimmunity in patients with alopecia areata remain unknown.

Main observation: A 13-year-old boy developed multiple hairless patches of focal hair loss with typical clinical and trichoscopy features of alopecia areata. Mycology examination of the scalp hair and epidermal scrapings reveled massive growth of Alternaria chlamydospora.

Conclusion: We hypothesize that fungal antigens (e.g. antigens involved in fungal melanin synthesis) may be possible triggers, contributing to autoimmune reactions in patients with alopecia areata. We discuss research data, which may indirectly support this hypothesis, however the concept has yet to be verified.

Keywords: Alternaria; IgE; Wood’s light; allergy; alopecia areata; autoimmunity; dermoscopy; fluorescence; fungus; hair; infection; melanin; pathogenesis; phaeohyphomycosis; tines capitis; trichoscopy.

Figure 1

Clinical appereance of the hairless areas in our patient were consistent with alopecia areata. Few small pustules were present within these areas (A). Trichoscopy of the hair-bearing margin showed typical features characteristic of alopecia areata, such as exclamation-mark hairs (arrow), yellow dots, black dots, and short, upright regrowing hairs and Pohl-Pinkus constrictions. A characteristic feature of exclamation mark hairs in AA is hypigmentation of the proximal end of the hair shaft, showing that increased disease activity in AA may be associated with decreased melanin content in the hair shaft (B). Additional trichoscopy findings included zigzag-like hairs (arrow, C). Some hairs were bent at a site of hemitranslucent nodules along the hair shaft, what may be consistent with trichorrhexis nodosa (arrow, D). UV-enhanced trichoscopy showed dots of light turquoise fluorescence, associated with hair follicle openings (arrow, E). Fungal culture showed prominent growth of Alternaria chlamydospora (F). Note the brownish color of these melanin-producing fungi.