Treatment for Pityriasis Versicolor
Selenium sulfide shampoo applied to affected areas once daily for 7 days is the first-line treatment for pityriasis versicolor, which presents as scaly hypopigmented macular lesions that fluoresce under Wood's lamp. 1
Diagnostic Confirmation
- Pityriasis versicolor is characterized by scaly hypopigmented or hyperpigmented macular lesions, typically located on the trunk, neck, and upper arms 2
- Wood's lamp examination is a valuable diagnostic tool, as affected areas will demonstrate characteristic fluorescence 3
- KOH preparation or fungal culture from skin scrapings can confirm the diagnosis by revealing fungal hyphae 4
- The causative organism is Malassezia furfur (previously known as Pityrosporum orbiculare), which is part of the normal skin flora but becomes pathogenic under certain conditions 5
Treatment Protocol
First-line Treatment
- Apply selenium sulfide shampoo to affected areas and lather with a small amount of water 1
- Allow the product to remain on the skin for 10 minutes 1
- Rinse thoroughly 1
- Repeat this procedure once daily for 7 days 1
Alternative Treatments
- Topical antifungal agents such as terbinafine cream or gel have shown high efficacy with cure rates of 79-100% after 2-4 weeks of treatment 6
- For resistant cases, oral antifungal medications like ketoconazole may be considered 4
Management of Post-inflammatory Hypopigmentation
- After successful treatment of the fungal infection, hypopigmented areas may persist as "pityriasis versicolor alba" 5
- Narrow-band UVB phototherapy can be effective for persistent hypopigmentation, helping to stimulate melanocyte activity and repigmentation 7
- Wood's lamp examination can help differentiate between active infection and post-inflammatory hypopigmentation 3
Prevention of Recurrence
- Complete drying of the skin after bathing is essential to prevent recurrence 8
- Daily changes of clothing, particularly in hot and humid environments, can help reduce fungal burden 8
- For patients with frequent recurrences, prophylactic use of selenium sulfide shampoo once or twice monthly may be beneficial 1
Clinical Pearls and Pitfalls
- Pityriasis versicolor is more common in hot, humid environments, which promote the pathogenic conversion of Malassezia 2
- The hypopigmentation may persist for weeks to months after successful eradication of the fungus 5
- Do not confuse with progressive macular hypomelanosis, which also presents with hypopigmented macules but shows characteristic follicular pink fluorescence under Wood's lamp due to Propionobacterium acnes 4
- Failure to improve with antifungal treatment should prompt reconsideration of the diagnosis 4