The Diagnosis: Blaschkoid Punctate Vitiligo
Based on the patient’s clinical appearance as well as the histologic findings, the diagnosis of vitiligo was made. Although vitiligo is certainly not uncommon and punctate vitiligo is a known clinical presentation,1 punctate vitiliginous depigmentation conforming to lines of Blaschko is unique. Follicular repigmentation in a patch of vitiligo potentially could lead to this “spotty” appearance, but our patient maintained that the band was never confluently depigmented and that small macules arose within normally pigmented skin. The patient’s adult age at onset makes this case even more unusual.
Follicular repigmentation in vitiligo is fairly well understood, as the perifollicular pigment is formed by upward migration of activated melanoblasts in the outer root sheath.2 Follicular depigmentation as well as selective or initial loss of melanocytes around hair follicles in early vitiligo has not been described. It is unclear if the seemingly folliculocentric nature of the patient’s vitiliginous macules was a false observation, coincidental, or actually related to selective melanocyte loss around follicles.
Blaschkoid distribution has been described in numerous skin disorders and is known to be based on genetic mosaicism.3 Most of these disorders are X-linked and/or congenital. However, many acquired skin conditions have been described exhibiting blaschkoid distribution, such as vitiligo, psoriasis, lichen planus, atopic dermatitis, and mycosis fungoides.4,5
Confettilike depigmentation has been described as an unusual clinical variant of vitiligo.1 It also has been reported after psoralen plus UVA therapy in patients with more classic vitiligo,6 numerous domestic chemicals,7 and in association with mycosis fungoides.8 In these cases, punctate lesions were disseminated, symmetric on extremities, or limited to areas exposed to chemicals.