Laboratory Studies

The diagnosis of tinea versicolor is usually made based on clinical examination findings; however, the diagnosis is easily confirmed with microscopic examination of scales soaked in 10-15% potassium hydroxide (KOH). See the images below.

Upon potassium hydroxide (KOH) examination, hyphae are visible and grow into strands within clumps of keratinocytes. Thick-walled spores frequently occur in grapelike clumps. Individual spores and short stubby hyphae float in the clear areas between clumps of keratinocytes. Many of the short hyphae are dystrophic.

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Mycelium strands and numerous spores observed on a potassium hydroxide (KOH) preparation of tinea versicolor. This combination is commonly referred to as "spaghetti and meatballs."

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Microscopic examination

Microscopic examination demonstrates the characteristic thick-walled spherical or oval yeast forms and coarse septate mycelium, often broken up into short filaments. This combination of mycelium strands and numerous spores is commonly referred to as "spaghetti and meatballs."

Liquid blue ink, methylene blue, or Swartz-Medrik stain can be added to the KOH preparation for better visualization of the causative organism.

Scales may also be removed using clear adhesive tape; they are then directly examined. The tape must be clear and is pressed several times over involved areas of skin. The tape is then lightly pressed, sticky side down, onto a microscope slide. A small drop of methylene blue or other appropriate stain is placed at the edge of the tape and allowed to run between the tape and the glass slide. Spores, often in grapelike clumps, and mycelium are easily seen. See the image below.

Clear adhesive tape can be pressed onto areas of tinea versicolor to collect hyphae and spores. The tape is then lightly pressed onto a glass slide, and a drop of methylene blue is placed at the edge of the tape. The methylene blue is allowed to run under the tape staining Malassezia furfur. The spores and hyphae easily are seen against a background clutter of keratinocytes and glue.

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A few reports in literature have recently stated that 1% Chicago Sky Blue 6B (CSB) staining with 10% KOH is a new promising contrast diagnostic method for pityriasis versicolor, with 100% of sensitivity compared with 60.9% in culture.^[7]

Cultures

M furfur is a dimorphic lipophilic organism, which is cultured only in media enriched with C12-sized to C14-sized fatty acids. It is not a dermatophyte, does not grow on DTM, and does not respond to griseofulvin therapy.

If inoculated into lipid-rich media, the scales of tinea versicolor show spherical yeasts that produce the mycelial phase of the normal flora yeast P orbiculare. Scales that show mycelium and clusters of oval yeasts on direct microscopy grow P ovale on culture.

Colonization by M furfur is especially dense in the scalp, the upper trunk, and the flexures. In patients with clinical disease, the organism occurs in both the filamentous (hyphal) and the yeast (spore) stage forms.

Imaging Studies

The disease does not require any imaging studies.

Wood lamp evaluation

Pityriasis versicolor showe blue-green fluorescence of macular dyschromic lesions if irradiated by ultraviolet light with wavelength of approximately 365 nm (black light). However, the test findings may be negative in individuals on antimycotic therapy of those who have recently showered because the fluorescent is water soluble.^[8]

Histologic Findings

The characteristic histological changes include hyperkeratosis, parakeratosis, and slight acanthosis with a mild perivascular inflammatory infiltrate in the upper dermis. The organism is usually present in the upper layers of the stratum corneum, and electron microscopy reveals invasion between and within the keratinized cells.

M furfur is detected by hematoxylin and eosin (H and E) stain alone, although periodic acid-Schiff (PAS) or methenamine-silver staining facilitates detection.

Treatment & Management

Dourmishev AL. Pityriasis versicolor. Iliev B, Mitov G, Radev M. Infectology. Academic publishing house; 2001. 812-3.
Prohić A, Jovović Sadiković T, Kuskunović-Vlahovljak S, Baljić R. Distribution of Malassezia Species in Patients with Different Dermatological Disorders and Healthy Individuals. Acta Dermatovenerol Croat. 2016 Dec. 24 (4):274-281. [QxMD MEDLINE Link].
Schmidt A. Malassezia furfur: a fungus belonging to the physiological skin flora and its relevance in skin disorders. Cutis. 1997 Jan. 59(1):21-4. [QxMD MEDLINE Link].
Nakabayashi A, Sei Y, Guillot J. Identification of Malassezia species isolated from patients with seborrhoeic dermatitis, atopic dermatitis, pityriasis versicolor and normal subjects. Med Mycol. 2000 Oct. 38(5):337-41. [QxMD MEDLINE Link].
Levy JM, Magro C. Atrophying pityriasis versicolor as an idiosyncratic T cell-mediated response to Malassezia: A case series. J Am Acad Dermatol. 2017 Apr. 76(4):730-735. [QxMD MEDLINE Link].
Day T, Scurry J. Vulvar pityriasis versicolor in an immunocompetent woman. J Low Genit Tract Dis. J Low Genit Tract Dis. 2014 Jul;. 18(3):e71-3. [QxMD MEDLINE Link].
Lodha N, Poojary SA. A Novel Contrast Stain for the Rapid Diagnosis of Pityriasis Versicolor: A Comparison of Chicago Sky Blue 6B Stain, Potassium Hydroxide Mount and Culture. Indian J Dermatol. 2015 Jul-Aug. 60(4):340-4. [QxMD MEDLINE Link]. [Full Text].
Wigger-Alberti W, Elsner P. Fluorescence with Wood's light. Current applications in dermatologic diagnosis, therapy follow-up and prevention. Hautarzt. 1997 Aug. 48(8):523-7. [QxMD MEDLINE Link].
[Guideline] Drake LA, Dinehart SM, Farmer ER, et al. Guidelines of care for superficial mycotic infections of the skin: Pityriasis (tinea) versicolor. Guidelines/Outcomes Committee. American Academy of Dermatology. J Am Acad Dermatol. 1996 Feb. 34(2 Pt 1):287-9. [QxMD MEDLINE Link].
Muhammad N, Kamal M, Islam T, Islam N, Shafiquzzaman M. A study to evaluate the efficacy and safety of oral fluconazole in the treatment of tinea versicolor. Mymensingh Med J. 2009 Jan. 18(1):31-5. [QxMD MEDLINE Link].
Rosen T. Mycological Considerations in the Topical Treatment of Superficial Fungal Infections. J Drugs Dermatol. 2016 Feb. 15 (2 Suppl):s49-55. [QxMD MEDLINE Link].
Cantrell WC, Elewksi BE. Can pityriasis versicolor be treated with 2% ketoconazole foam?. J Drugs Dermatol. 2014 Jul. 13(7):855-9. [QxMD MEDLINE Link].
Gupta AK, Lyons DC. Pityriasis versicolor: an update on pharmacological treatment options. Expert Opin Pharmacother. 2014 Aug. 15(12):1707-13. [QxMD MEDLINE Link].
Gupta AK, Lane D, Paquet M. Systematic review of systemic treatments for tinea versicolor and evidence-based dosing regimen recommendations. J Cutan Med Surg. 2014 Mar-Apr. 18(2):79-90. [QxMD MEDLINE Link].
Neamsuvan O, Bunmee P. A survey of herbal weeds for treating skin disorders from Southern Thailand: Songkhla and Krabi Province. J Ethnopharmacol. 2016 Dec 4. 193:574-585. [QxMD MEDLINE Link].
Gobbato AA, Babadópulos T, Gobbato CA, Ilha Jde O, Gagliano-Jucá T, De Nucci G. A randomized double-blind, non-inferiority Phase II trial, comparing dapaconazole tosylate 2% cream with ketoconazole 2% cream in the treatment of Pityriasis versicolor. Expert Opin Investig Drugs. 2015. 24 (11):1399-407. [QxMD MEDLINE Link].
Badri T, Hammami H, Bzioueche N, Zouari B, Mokhtar I. Comparative clinical trial: fluconazole alone or associated with topical ketoconazole in the treatment of pityriasis versicolor. Tunis Med. 2016 Feb. 94 (2):107-11. [QxMD MEDLINE Link].
Tsunemi Y. Oral Antifungal Drugs in the Treatment of Dermatomycosis. Med Mycol J. 2016. 57 (2):J71-5. [QxMD MEDLINE Link].

Media Gallery

In patients with lighter skin color, lesions frequently are a light tan or salmon color.
Upon potassium hydroxide (KOH) examination, hyphae are visible and grow into strands within clumps of keratinocytes. Thick-walled spores frequently occur in grapelike clumps. Individual spores and short stubby hyphae float in the clear areas between clumps of keratinocytes. Many of the short hyphae are dystrophic.
Scale is frequently difficult to appreciate upon clinical examination.
This individual developed skin discoloration and mild itching every summer for the past few years. These patients should be instructed on the prophylactic use of topical therapy.
This superficial plaque of tinea versicolor is located in the right antecubital fossa of an adult. This appearance and distribution is uncommon but not rare. A potassium hydroxide (KOH) preparation confirmed the diagnosis.
Although tinea versicolor is uncommon in children in temperate climates, when it does occur, it is more likely to be atypical in distribution. This 7-year-old boy had areas of tinea versicolor across the forehead and both temples. He was in good health and lived in Washington state when he was diagnosed.
In some patients, the areas affected by tinea versicolor are not always obvious. In this patient, the abnormal areas are hypopigmented.
Clear adhesive tape can be pressed onto areas of tinea versicolor to collect hyphae and spores. The tape is then lightly pressed onto a glass slide, and a drop of methylene blue is placed at the edge of the tape. The methylene blue is allowed to run under the tape staining Malassezia furfur. The spores and hyphae easily are seen against a background clutter of keratinocytes and glue.
Some patients present with extensive tinea versicolor. This patient related that his discoloration had been present for more than 20 years. The light-colored areas on the abdomen are the normal areas of skin. Although topical therapy alone is usually effective, this patient may benefit from initial therapy with oral ketoconazole, followed by selenium sulfide applications in the shower 2-3 times a month.
Significant hyperpigmentation caused by a tinea versicolor infection.
Confluent and reticulated Gougerot and Carteaud papillomatosis.
Mycelium strands and numerous spores observed on a potassium hydroxide (KOH) preparation of tinea versicolor. This combination is commonly referred to as "spaghetti and meatballs."