Can Selenium Sulfide Shampoo Be Used on the Trunk for Pityriasis Versicolor in Children?
Yes, selenium sulfide shampoo can be safely and effectively applied to the trunk for treating pityriasis versicolor in children, though safety and effectiveness in infants have not been established. 1
FDA-Approved Indication and Application
Selenium sulfide is FDA-approved specifically for the treatment of tinea versicolor (pityriasis versicolor) when applied to body surfaces, not just the scalp. 1
The medication can be applied to the trunk and other affected body areas, as the FDA label explicitly addresses "body surfaces" for tinea versicolor treatment. 1
The standard concentration used is 2.5% selenium sulfide lotion/shampoo, which has demonstrated efficacy in multiple clinical studies. 1, 2, 3
Dosing and Application Protocol
Apply selenium sulfide 1-2.5% to the entire affected skin area (including trunk) for 5-15 minutes daily for 18 days, as this regimen has proven equally effective whether applied for 5 minutes, 15 minutes, or 12 hours. 2
The medication should be thoroughly rinsed after application to minimize potential hair discoloration and skin irritation. 1
Alternative regimens include 2.5% selenium sulfide shampoo applied once weekly for 3 weeks, which achieved 85% cure rates in clinical trials. 3
Safety Considerations in Pediatric Patients
Safety and effectiveness in infants have not been established, so caution is warranted in this age group. 1
Selenium sulfide should NOT be used when acute inflammation or exudation is present, as increased absorption may occur. 1
Systemic absorption is minimal: fluorimetric analysis showed no significant increase in urinary selenium excretion after 18 days of whole-body application for 5 minutes daily, indicating poor percutaneous absorption and low systemic toxicity risk. 2
Efficacy Evidence
Clinical studies demonstrate that selenium sulfide is highly effective for pityriasis versicolor, with cure rates of 85-95% when applied to body surfaces. 3
Comparative trials show selenium sulfide (2.5%) has similar efficacy to ketoconazole shampoo (2%), with 85% of patients cured after 3 weekly applications. 3
The American Academy of Pediatrics recommends topical treatments as first-line therapy in children due to their favorable safety profile. 4
Common Pitfalls and Adverse Effects
Avoid use during pregnancy (Category C) when treating tinea versicolor on body surfaces, as fetal harm cannot be ruled out. 1
Potential adverse effects include skin irritation, occasional increase in hair loss, and hair discoloration (minimized by thorough rinsing). 1
Oiliness or dryness of skin may occur, similar to other shampoo formulations. 1
Prophylaxis to Prevent Recurrence
Prophylactic treatment is mandatory to avoid recurrence, as pityriasis versicolor frequently relapses. 5
Proper cleaning of combs and brushes is recommended to prevent reinfection. 4
Relapse rates in clinical trials ranged from 5-11% during 3-4 month follow-up periods with selenium sulfide treatment. 3, 6