Pityriasis Versicolor

What is it?

Pityriasis versicolor (also known as tinea versicolor) is a common superficial fungal infection of the skin caused by Malassezia yeasts, organisms that normally reside on human skin. The condition manifests as multiple well-demarcated patches of altered skin color—either lighter or darker than the surrounding skin—accompanied by fine scaling, predominantly affecting the trunk and proximal extremities.

Who is affected?

Pityriasis versicolor is one of the most common superficial fungal infections worldwide, with particularly high prevalence in tropical and subtropical climates.

• Prevalence: Affects approximately 1 in 25 people (2-8%) in temperate climates; prevalence rises to 40-50% in tropical regions
• Age demographics: Most commonly affects adolescents and young adults (peak incidence between 15-24 years); onset typically coincides with increased sebaceous gland activity during puberty; uncommon in children and the elderly
• Gender distribution: Affects males and females equally, though some studies report a slight male predominance
• Risk factors: Hot, humid climates; excessive sweating (hyperhidrosis); oily skin; immunosuppression; systemic corticosteroid use; malnutrition; genetic predisposition; use of occlusive clothing or topical oils

What causes it?

Pityriasis versicolor results from the overgrowth of Malassezia yeasts, which are part of the normal skin flora:

• Malassezia species: M. globosa and M. furfur are the most commonly implicated species; the organism transitions from its normal yeast form to a pathogenic mycelial (hyphal) form under favorable conditions
• Pathogenic mechanism: The mycelial form produces azelaic acid and other metabolites that inhibit tyrosinase (an enzyme essential for melanin production), leading to hypopigmentation; additionally, the fungus may stimulate melanocyte hyperactivity in some cases, causing hyperpigmentation
• Predisposing factors: Warm, humid environments promote fungal overgrowth; increased sebaceous gland activity (sebum serves as a nutrient for Malassezia); altered immune responses; hormonal changes
• Not contagious: Despite being caused by a fungus, pityriasis versicolor is not transmitted from person to person, as Malassezia is already present on everyone's skin

What are the clinical features?

Pityriasis versicolor characteristically presents as multiple round to oval patches with fine powdery scaling on the surface.

Pigmentation variants:

• Hypopigmented form (most common in darker skin tones): Lighter patches that become more noticeable after sun exposure, as the affected skin fails to tan; the fungus produces azelaic acid, which inhibits melanin production
• Hyperpigmented form: Pink, tan, or brown patches, more commonly seen in fair-skinned individuals
• Erythematous form: Red or pink patches, sometimes with mild pruritus (itching)

Distribution:

• Predominantly affects the trunk (chest, back, shoulders) and proximal upper extremities
• May extend to the neck, abdomen, and groin
• Facial involvement is more common in children
• Lesions tend to coalesce into larger confluent patches

Symptoms:

• Usually asymptomatic or mildly pruritic
• Cosmetic concern is the primary complaint
• Fine, powdery scaling evident on gentle scratching (evoked scale sign)
• Lesions may become more noticeable in summer when surrounding skin tans but affected areas do not

How is it diagnosed?

Diagnosis is usually clinical, based on the characteristic appearance and distribution of lesions:

• Clinical examination: Recognition of the typical multi-colored (versicolor) patches with fine scaling on the trunk; the evoked scale sign (fine powdery scaling upon gentle scratching) is a useful clinical indicator
• Wood's lamp examination: Affected areas may fluoresce golden-yellow or copper-orange under ultraviolet light; however, fluorescence is not always present
• KOH (potassium hydroxide) preparation: Microscopic examination of skin scrapings reveals the characteristic "spaghetti and meatballs" appearance—short, thick hyphae (spaghetti) mixed with round yeast cells (meatballs); this is considered the confirmatory test
• Dermoscopy: Reveals irregular whitish or brownish structureless areas with fine scaling
• Differential diagnosis: Must be distinguished from vitiligo (no scaling, completely depigmented), pityriasis alba (common in children, face predominantly), post-inflammatory hypopigmentation, seborrheic dermatitis, and tinea corporis

What treatment options are available?

Treatment aims to eradicate the fungal overgrowth and restore normal skin pigmentation:

Topical antifungal therapy (first-line for limited disease):

• Ketoconazole 2% shampoo or cream: Applied to affected areas; shampoo formulation used as a body wash (left on for 5-10 minutes before rinsing); clinical response rates of 69-73%
• Selenium sulfide 2.5% lotion or shampoo: Applied as a body wash; effective and widely available
• Ciclopirox cream or solution: Alternative topical option
• Zinc pyrithione shampoo: Available over the counter; useful for mild cases and maintenance

Oral antifungal therapy (extensive or recurrent disease):

• Itraconazole: Effective option for widespread involvement
• Fluconazole: Alternative systemic agent

Important considerations:

• Pigmentation changes may persist for weeks to months after successful treatment, as repigmentation requires new melanin production and sun exposure
• Mycological cure (elimination of the fungus) occurs before cosmetic improvement

Recurrence prevention:

• Recurrence is common (approximately 60-80% within 2 years without prophylaxis)
• Monthly prophylactic use of ketoconazole shampoo or periodic oral antifungal therapy can reduce recurrence
• Itraconazole prophylaxis (200 mg twice daily, one day per month for 6 months) achieves 88% mycological cure versus 57% with placebo

Prognosis:

• Pityriasis versicolor is a benign condition with excellent response to treatment
• Complete repigmentation may take several months, even after successful antifungal treatment
• Recurrence is the main challenge, particularly in warm climates or in patients with predisposing factors

Key points for patients

• Pityriasis versicolor is a common, harmless fungal infection that is not contagious
• The color changes in the skin are temporary and will resolve after treatment, though repigmentation may take several weeks to months
• Treatment is effective, but recurrence is common; regular use of antifungal shampoo as a body wash can help prevent recurrence
• When to seek medical attention: Expanding or worsening patches despite over-the-counter treatment, significant itching, or uncertainty about the diagnosis
• Prevention strategies: Use antifungal shampoo as a body wash periodically (especially before summer); wear breathable, loose-fitting clothing; avoid excessive use of skin oils; manage excessive sweating