2.3.3 Pityriasis Versicolor
Grading & Level of Importance: B
Most common in young adults during spring and summer seasons.
Superficial cutaneous mycosis caused by lipophilic Malassezia yeasts (primarily M. globosa) with hypo- and hyperpigmented macules.
Aetiology & Pathogenesis
Causative lipophilic Malassezia yeasts belong to the resident flora of human skin. Various predisposing factors trigger hyphal growth stage.
Predisposing factors: sweating, humid climate, immunosuppression.
Signs & Symptoms
Variable picture; several clinical types:
- Hyperpigmented type: small, yellow-brown macules, disseminated, fine scale, sometimes modest pruritus.
- Depigmented type (pityriasis versicolor alba): small white macules in dark-skinned or tanned individuals.
- Erythematous type: erythematous macules with infiltrate and only minimal scale.
- Follicular type: acneiform, often at the back.
- Atypical forms: solitary or few lesions, often in atypical sites.
Upper trunk, less often lower trunk and proximal extremities.
Laboratory & other workups
KOH examination or stripping with cellophane tape; methylene stain for grouped spores and hyphae on scales under microscope (spaghetti and meatballs pattern).
Hyphae and spores in the stratum corneum and in the acroinfundibula.
Usually persistent or recurrent, sometimes clears spontaneously.
Clinical features, microscopic examination of scales, yellow-orange fluorescence under Wood’s light (365 nm).
Guttate hypomelanosis, vitiligo, pityriasis alba, pityriasis rosea, tinea corporis, seborrheic dermatitis, erythrasma.
Prevention & Therapy
Prevention: careful drying of skin after shower, wearing breathable fabrics to decrease sweating, avoidance of tight clothing, avoidance of highly moisturizing skin products. Treatment of scalp reservoir.
Topical treatment of the entire body (shampoos containing imidazoles, selenium sulfide, ciclopirox or zinc pyrithione); in cases with frequent recurrences or widespread involvement: systemic anti-fungals such as itraconazole.
- Statement 1 If a patient is diagnosed with pityriasis versicolor, all family members must also be treated.
- Which statement is true?
- Which organism causes pityriasis versicolor?
- Which of the following techniques can confirm or rule out the diagnosis of pityriasis versicolor?
- Which statement is false?
- How can one distinguish between vitiligo and pityriasis versicolor?
- Which of these are predisposing factors for pityriasis versicolor?
- Which of these disorders belong to the differential diagnostic considerations for pityriasis versicolor?
- Which of these treatments are appropriate for pityriasis versicolor?
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