Tinea versicolor

Tinea versicolor is a common superficial fungal infection of the skin caused by Malassezia species. It is characterized by discolored patches on the trunk, neck, and shoulders. Though usually asymptomatic, it can cause cosmetic concerns and recurrent episodes.

Etiology and Risk Factors

Fungal Agent

Tinea versicolor is caused by Malassezia, a lipophilic yeast that is part of the normal skin flora. Under certain conditions, it transitions from a commensal organism to a pathogenic form, producing skin lesions:

• Malassezia species: Includes M. globosa, M. furfur, and M. sympodialis.
• Pathogenic mechanisms: The yeast produces lipases that degrade skin lipids, leading to irritation and disruption of melanocyte function.

Predisposing Factors

Several factors increase the risk of developing tinea versicolor:

• Warm and humid climate: Favors fungal growth and proliferation.
• Excessive sweating (hyperhidrosis): Provides a moist environment for Malassezia overgrowth.
• Oily skin: Sebaceous gland activity supports the growth of lipophilic yeast.
• Immunosuppression: Conditions like HIV infection or corticosteroid use can increase susceptibility.
• Hormonal changes: Puberty and other hormonal fluctuations may predispose to infection.

Pathophysiology

The pathophysiology of tinea versicolor involves a shift of Malassezia from a harmless commensal to a pathogenic yeast. Key mechanisms include:

• Transition from yeast to pathogenic form: Triggered by environmental and host factors such as humidity, heat, and sebaceous secretions.
• Effects on melanocyte function: Fungal metabolites disrupt melanin production, causing hypopigmented or hyperpigmented lesions.
• Disruption of skin pigmentation: The imbalance in melanocyte activity results in characteristic discolored macules and patches, which may be more noticeable after sun exposure.

Clinical Presentation

Skin Lesions

Tinea versicolor typically presents with distinct skin changes, which are the hallmark of the disease:

• Hypopigmented or hyperpigmented macules: Small, well-demarcated patches that may be lighter or darker than surrounding skin.
• Fine scaling: Subtle, powdery scale is often present and may be more apparent after scraping the lesion.
• Distribution patterns: Commonly affects the trunk, shoulders, neck, and upper arms.

Symptoms

Most patients experience minimal symptoms, but some may report:

• Mild pruritus, especially in warm or humid conditions.
• Cosmetic concerns due to visible discoloration.

Complications

Although generally benign, tinea versicolor may have complications, particularly if untreated or recurrent:

• Recurrence of lesions due to persistence of Malassezia on the skin.
• Secondary bacterial infection in areas of scratching.

Diagnosis

Clinical Evaluation

Diagnosis of tinea versicolor is primarily clinical, based on the appearance and distribution of lesions:

• Inspection of hypopigmented or hyperpigmented macules with fine scaling.
• Assessment of lesion distribution on typical sites such as the trunk and shoulders.

Diagnostic Tests

Laboratory tests may be used to confirm the diagnosis or in atypical cases:

• Wood’s lamp examination: Lesions may fluoresce yellow-green under ultraviolet light.
• KOH (potassium hydroxide) microscopy: Reveals the characteristic “spaghetti and meatballs” appearance of hyphae and spores.
• Fungal culture: Rarely required, reserved for unusual or resistant cases.

Differential Diagnosis

Conditions that may mimic tinea versicolor include:

• Vitiligo
• Pityriasis rosea
• Seborrheic dermatitis
• Post-inflammatory hypopigmentation

Management

Topical Antifungal Therapy

Topical treatments are the first-line therapy for most cases of tinea versicolor. Common options include:

• Azoles: Ketoconazole, clotrimazole, and miconazole applied as creams, gels, or shampoos.
• Selenium sulfide and zinc pyrithione: Shampoos or lotions applied to affected areas to reduce fungal load.

Systemic Therapy

Oral antifungal agents are indicated for extensive, refractory, or recurrent cases:

• Fluconazole or itraconazole: Short courses are effective in eradicating the infection.
• Indications: Widespread lesions, involvement of large body surface area, or failure of topical therapy.

Adjunctive Measures

Additional strategies help prevent recurrence and support treatment effectiveness:

• Maintaining proper skin hygiene and avoiding excessive sweating.
• Wearing loose clothing to reduce moisture accumulation.
• Periodic prophylactic use of antifungal shampoos in recurrent cases.

Prognosis

The prognosis of tinea versicolor is generally excellent with appropriate treatment. Key points include:

• Response to treatment: Most patients experience resolution of lesions within weeks of therapy.
• Recurrence rates: Recurrence is common due to persistence of Malassezia on the skin; preventive measures may reduce recurrence.
• Long-term outcomes: Skin pigmentation may take several weeks to normalize even after successful antifungal therapy.

Prevention

Preventing tinea versicolor involves measures that reduce fungal overgrowth and minimize recurrence. Key preventive strategies include:

• Lifestyle modifications: Avoiding prolonged exposure to heat and humidity, wearing breathable clothing, and practicing regular skin hygiene.
• Prophylactic antifungal agents: Periodic use of antifungal shampoos or topical agents on high-risk areas, especially in patients with recurrent infections.
• Managing underlying risk factors: Controlling excessive oiliness of the skin and minimizing immunosuppressive conditions when possible.

References

1. Bolognia JL, Schaffer JV, Cerroni L. Dermatology. 4th ed. Philadelphia: Elsevier; 2018.
2. Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 7th ed. Philadelphia: Elsevier; 2019.
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4. Shin HT, Park YM, Lee JH, et al. Clinical and mycological characteristics of tinea versicolor in Korea. Mycoses. 2014;57(12):737-742.
5. Rinaldi MG. Pityriasis versicolor. In: Elewski BE, editor. Skin Disease: Diagnosis and Treatment. New York: Springer; 2012. p. 215-220.
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7. Gaitanis G, Magiatis P, Hantschke M, et al. The Malassezia genus in skin and systemic diseases. Clin Microbiol Rev. 2012;25(1):106-141.