B36.0 Pityriasis versicolor

Name of the Condition

• Pityriasis versicolor

Summary

Pityriasis versicolor is a superficial fungal infection of the skin that causes discolored patches. It is caused by the yeast Malassezia and typically affects areas with high sebum production, such as the trunk, neck, and arms. The condition is generally mild and cosmetic but may recur.

Causes

Pityriasis versicolor is caused by the yeast Malassezia, which is part of the normal skin flora. Overgrowth of this yeast, often triggered by factors like heat, humidity, or hormonal changes, leads to the characteristic skin changes. The yeast produces pigments that alter skin color, resulting in lighter or darker patches.

Risk Factors

• Warm, humid climates
• Excessive sweating
• Oily skin
• Weakened immune system
• Use of oily skin products
• Pregnancy or hormonal changes

Symptoms

• Discolored patches on the skin (lighter or darker than surrounding skin)
• Scaling or mild itching
• Patches that may merge and spread
• Predilection for the trunk, neck, or upper arms

Diagnosis

Diagnosis is typically made through clinical examination of the skin. A Wood's lamp may be used to highlight the patches, and skin scrapings can be examined microscopically to confirm the presence of Malassezia yeast.

Treatment Options

• Topical antifungal creams or shampoos (e.g., selenium sulfide, ketoconazole)
• Oral antifungal medications for widespread or recurrent cases
• Maintaining good skin hygiene and avoiding excessive sweating

Prognosis and Follow-Up

With treatment, the infection usually resolves within weeks, though skin discoloration may persist for months. Recurrence is common, especially in warm climates or with predisposing factors. Follow-up may be recommended to monitor for recurrence or adjust treatment.

Complications

• Persistent skin discoloration even after treatment
• Recurrence, particularly in humid environments
• Rarely, secondary bacterial infection if the skin is scratched

Lifestyle & Prevention

• Keep skin clean and dry
• Use antifungal shampoos or soaps if prone to recurrence
• Avoid tight or non-breathable clothing
• Limit time in hot, humid conditions
• Use non-comedogenic skin products

When to Seek Professional Help

• If patches spread rapidly or become painful
• If over-the-counter treatments are ineffective
• If signs of infection (e.g., pus, increased redness) develop
• If you have a weakened immune system and suspect a fungal infection

Tips for Medical Coders

• Code B36.0 is specific to pityriasis versicolor and should be used when the condition is documented. Ensure the diagnosis aligns with clinical findings, as the condition may present with variable skin discoloration. Documentation should support the use of this code, including any relevant clinical notes or test results.