Summary
Pityriasis versicolor is a benign, superficial fungal infection most commonly caused by Malassezia furfur or Malassezia globosa. Although the condition occurs worldwide, the incidence is higher in tropical climates. It typically manifests as a well-demarcated, macular rash with round or oval hyperpigmented, hypopigmented, or erythematous lesions that often coalesce. The seborrheic areas of the upper trunk and neck are primarily affected, and the lesions are more noticeable after UV exposure because the surrounding skin darkens while the affected skin does not. Pityriasis versicolor is usually a clinical diagnosis; however, potassium hydroxide (KOH) microscopy of skin scrapings that show hyphae and spores in a characteristic “spaghetti-and-meatballs” pattern confirms the diagnosis. Topical drugs such as selenium sulfide and ketoconazole are recommended for initial treatment; systemic therapy is reserved for extensive or refractory disease. Lesions will resolve completely over time, but recurrences are common.
Pityriasis versicolor was previously known as tinea versicolor, as it was believed to be a dermatophyte infection. Some sources still refer to the condition by its original name.
Epidemiology
- Occurs worldwide, with a higher incidence in tropical climates
- More prevalent in healthy individuals 21–30 years of age [1]
Epidemiological data refers to the US, unless otherwise specified.
Etiology
Pathogens
- Malassezia spp. (previously known as Pityrosporum): most commonly Malassezia globosa and Malassezia furfur
- Dimorphic, lipophilic yeast-like fungi that are part of the normal skin flora
- Not contagious
Risk factors
- Hot and humid climates [2][3]
- Excessive sweating, seborrhea, and oily skin
- Immunosuppression
- Cushing syndrome
- Genetic predisposition
Pathophysiology
- Malassezia spp. infect the stratum corneum → lipid degradation → production of acids that inhibit tyrosinase and damage melanocytes → hypopigmentation
- Inflammatory response to pathogens → hyperpigmentation
Clinical features
-
Symmetrically affects the seborrheic areas of the upper trunk (chest, shoulders, upper arms) and neck [4]
- In children: Facial involvement is also common.
- Immunocompromised individuals: Extensive disease may be seen.
- Rash appears as round or oval macules 1–3 cm in diameter [5]
- Lesions often coalesce into well-demarcated irregular patches. [4]
-
Color of the lesions may vary in the affected individual (i.e., hypopigmented, hyperpigmented, erythematous) ; [4]
- Lesions may change color with seasons (e.g., lighter than surrounding skin during summer, darker than surrounding skin in winter).
- Hypopigmentation is typical in individuals with darker skin. [6]
- May be mildly pruritic [4][7]
- Fine, bran-like, subtle scaling if the skin is stretched or gently scraped (evoked scale sign) [4][6][8]
Lesions are more noticeable after UV exposure because the surrounding skin darkens while the affected skin does not. [4]
Diagnosis
- Diagnosis is usually clinical. [4][9]
- Wood lamp examination can support the diagnosis; affected areas fluoresce yellow-green. [4][5]
- KOH microscopy confirms the diagnosis. [4][9]
A fungal culture is usually not performed as the yeast can be part of normal skin flora. [4]
Differential diagnoses
- Vitiligo
- Seborrheic dermatitis
- Pityriasis rosea
- Pityriasis alba
- Guttate psoriasis
- Erythrasma
- Mycosis fungoides
-
Pityrosporum folliculitis: an infection of hair follicles caused by Malassezia spp. that typically manifests as pruritic, papulopustular eruptions. [2][10]
- Usually occurs in immunocompromised patients (e.g., HIV, immunosuppressive therapy, stress, diabetes, steroid therapy)
- Often difficult to distinguish from acne vulgaris (and may also occur concurrently with it)
The differential diagnoses listed here are not exhaustive.
Treatment
Localized disease [4][5]
- First-line: topical therapy
- Options include: [4][5][7]
- Azoles: clotrimazole , ketoconazole (off-label in children aged < 12 years) [4][5]
- Selenium sulfide (off-label in children aged < 12 years) [4][5]
- Zinc pyrithione (off-label) [11]
- Terbinafine (off-label in children) [4]
- Discoloration may take months to resolve; signs of treatment response include: [4]
- Disappearance of scale
- Absence of “spaghetti-and-meatball” appearance on KOH preparation
- Recurrences are common; consider once-weekly or once-monthly prophylactic topical therapy (off-label). [4]
Extensive or refractory disease [4][5]
- Consider systemic therapy; consult specialists for pediatric dosages.
- Preferred: fluconazole (off-label) [4][5]
- Alternative: itraconazole (off-label) [4]
Systemic griseofulvin and terbinafine are not effective in treating pityriasis versicolor. [5]