Common Contact Allergens in Patients with Palmoplantar and Scalp Psoriasis and Impact of their Avoidance on Dermatology Life Quality Index: A Hospital-Based Study

BACKGROUND: Scalp psoriasis and psoriasis limited to palms and/or soles have been referred to as difficult to control psoriasis. Contact allergy has long been suspected to aggravate existing lesions and cause resistance to therapy in these psoriasis variants. OBJECTIVES: The objective of the study was to assess common contact allergens in patients with palmoplantar and scalp psoriasis and the impact of their avoidance on dermatology life quality index (DLQI). MATERIALS AND METHODS: A total of 54 patients with palmoplantar and scalp psoriasis were patch tested with Indian Standard Series. The patch test results were read on day 2 and day 4. DLQI was calculated before patch testing and at 1 month and 3 month in patch test positive patients after instructing allergen avoidance. RESULTS: Sixteen out of fifty-four patients (29.62%) showed positive patch test reactions. Metal antigens like nickel and cobalt were the most common sensitizers identified. Statistically significant improvement in DLQI was observed at 1 month and at 3 month of allergen avoidance. CONCLUSION: Patch testing is a useful test to determine the triggering or aggravating antigens in patients with palmoplantar and scalp psoriasis and subsequent allergen avoidance should be stressed on.