Derm Dx: Can You Diagnose This Patient’s Rash?

Tinea versicolor, also referred to as pityriasis versicolor, is a common superficial cutaneous fungal infection caused by Malassezia, a yeast-like organism. Although Malassezia is a normal component of skin flora, infection may manifest once the organism converts to its pathogenic...

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Tinea versicolor, also referred to as pityriasis versicolor, is a common superficial cutaneous fungal infection caused by Malassezia, a yeast-like organism. Although Malassezia is a normal component of skin flora, infection may manifest once the organism converts to its pathogenic hyphal form.¹ M globosa, M sympodialis, and M furfur are the most common species that cause tinea versicolor.² Certain genetic, environmental, and immunologic factors promote development; these include moisture, heat, diabetes, Cushing disease, immunosuppression, and corticosteroid intake.^1,3 Tinea versicolor often arises between childhood and adolescence, and may be attributed to hormonal changes that result in increased sebum production favoring fungal growth.¹

Tinea versicolor presents as well-demarcated, finely scaling patches.¹ The lesions can either be hyperpigmented, hypopigmented, or erythematous. Although typically asymptomatic, patients with tinea versicolor may experience mild pruritus, especially in humid environments.² Tinea versicolor most commonly manifests on the torso, neck, or proximal extremities. The fine scale on the lesions becomes more apparent when the affected skin is stretched or scraped, which is known as the “evoked scale sign.”¹

Tinea versicolor is usually diagnosed based on clinical appearance. Differential diagnoses include vitiligo, pityriasis alba, and pityriasis rosea.⁴ Potassium hydroxide preparation of scales reveals numerous short hyphae and yeast forms that resemble “spaghetti and meatballs.”^1,2  Antifungal therapies are curative; however, pigmentary changes may remain for several months following treatment, even with successful eradiation of the pathogenic organism.²

Julie Grandinetti, PA-C, is on staff at Mount Sinai Hospital in the Bronx, New York, and Stephen Schleicher, MD, is director of the DermDox Center for Dermatology, as well as associate professor of medicine at Commonwealth Medical College and clinical instructor of dermatology at Arcadia University and Kings College.

References

1. Renati S, Cukras A, Bigby M. Pityriasis versicolor. BMJ. 2015;350:h1394.  
2. Schachner L, Hansen R. Pediatric Dermatology. 4th ed.  Maryland Heights, MO: Mosby; 2010.
3. Ghosh SK, Dey SK, Saha I, Barbhuiya JN, Ghosh A, Roy AK. Pityriasis versicolor: a clinicomycological and epidemiological study from a tertiary care hospital. Indian J Dermatol. 2008;53(4):182-185.
4. Rivard SC. Pityriasis versicolor: avoiding pitfalls in disease diagnosis and therapy. Mil Med. 2013;178(8):904-906.