Pityriasis versicolor
Also called tinea versicolor, Malassezia versicolor
Malassezia yeast overgrowth painting the sebaceous trunk with finely scaling macules that refuse to match the surrounding skin, lighter on tanned or dark skin, pinkish-brown on pale, hence 'versicolor'. Trivial to treat, famous for the pigment lagging months behind the cure.
Medium-deep skin tone: the patches are paler than the surrounding skin
How it looks
Multiple coalescing hypopigmented macules with fine branny scale on gentle scraping, scattered over the upper trunk and shoulders.
Rose is the lesion, grey the pattern the lesions make, green where on the body it lives.
Across skin tones
In deeply pigmented skin the hypopigmented form dominates and is more distressing, inviting confusion with vitiligo; versicolor keeps some pigment and scales on scraping, while vitiligo is chalk-white, scale-free, and fluoresces stark under Wood lamp.
Symptoms & course
- Asymptomatic or mildly itchy
- More visible after sun exposure, when affected areas fail to tan
- Recurs seasonally in the predisposed
Diagnostic approach
- Clinical; the 'evoked scale' scratch sign
- KOH shows the spaghetti-and-meatballs yeast when confirmation is wanted
Differential, and how to separate them
- Vitiligo
Favours it: Acquired pale patches on the trunk
Against it: Vitiligo is completely depigmented with no scale; versicolor is hypopigmented and flakes when scraped
- Pityriasis rosea
Favours it: Oval scaly truncal macules
Against it: PR is inflamed, follows a herald patch, and clears in weeks; versicolor is indolent and recolours slowly
- Seborrheic dermatitis
Favours it: Same yeast, same sebaceous territory
Against it: Seborrheic dermatitis is inflamed greasy scale in the zones, not discrete colour-shifted macules
Management principles
- Topical antifungal shampoos or azoles to the whole trunk, not lesion by lesion
- Short oral azole courses for extensive or recurrent disease
- Tell the patient the colour takes months to return after the yeast is gone, or they will report treatment failure
Clinical pearl: Treatment success is judged by scale, not colour: no flake on scraping means the yeast is dead, whatever the pigment still says.
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