Hyperpigmentation Associated with the Use of Topical Cidofovir for Treatment of Trichodysplasia Spinulosa in an Immunosuppressed Adult: Case Report and Review of the Literature

Trichodysplasia spinulosa (TS) is a rare, opportunistic infectious skin disease caused by the polyoma virus. Clinically, TS is characterized by follicular papules, keratin spicules, and alopecia most classically in a midfacial distribution. Since its discovery in 2010, no standard of treatment has been established, though use of oral acitretin, valganciclovir, lefludomide, topical cidofovir, physical extraction, and modification of immunosuppressive medications have been reported in the literature. We describe the case of a 52-year old female with a painful midfacial eruption and alopecia of the bilateral eyebrows ultimately diagnosed with TS and treated with topical cidofovir 3%. Though the TS eruption resolved, treatment resulted in hyperpigmentation of the affected area. Hyperpigmentation associated with cidofovir use has been reported in cases of molluscum contagiosum, however no such association has been described in the treatment of TS to our knowledge. Therefore, we report this case to highlight an underreported adverse effect of topical cidofovir in the setting of this rare disease.