Contact Sensitization to Hair Care Allergens in Scalp Seborrheic Dermatitis: Associations with Disease Severity and Microbiota Profiles

The study investigated the relationship between contact sensitization and scalp microbiota in scalp seborrheic dermatitis (SSD) by testing 63 participants with 62 allergens. Results showed that common sensitizers included cobalt chloride, cetrimonium bromide, and minoxidil, with sensitization patterns linked to age, sex, disease duration, and severity. Increased transepidermal water loss was associated with fragrance and preservative allergens. Minoxidil sensitization was negatively associated with Malassezia, while other allergens correlated with Candida, Staphylococcus, and Corynebacterium. The study concludes that SSD patients exhibit distinct sensitization patterns related to clinical characteristics, barrier dysfunction, and microbiota changes, suggesting that patch test results should consider allergen exposure, skin barrier status, and microbial imbalance.