P011 Patch test outcomes in 226 patients from a dermatology department: a 5-year audit (2020–2025)

Abstract

A review of patch test data from January 2020 and September 2025 was conducted. Patient demographics, affected sites prompting referral, allergen positivity rates and clinical outcomes were recorded. In total 226 patients (mean age 43.1 years, range 4–97) underwent patch testing. Adults comprised 91.1% (n = 206) and overall there was a female predominance (71.2%, n = 161). Most patients were referred by dermatologists (73.0%, n = 165) or general practitioners (20.3%, n = 46). The mean waiting time to patch testing was 237 days (range 4–1706). All patients were tested against the British Society for Cutaneous Allergy (BSCA) baseline series, with the addition of the BSCA facial and medicament series as clinically indicated. Affected sites prompting referral were head and neck (33.1%, 122 of 368), hands (21.2%, 78 of 368), feet (3.3%, 12 of 368), genitals (1.4%, 5 of 368) and rest of the body (37.8%, 139 of 368). Positive reactions occurred in 75.7% of patients (n = 171). The highest positivity rates for common allergens in the baseline series were nickel (21.7%), fragrance mix I/II (15.5%), limonene (13.7%), linalool (11.9%), cobalt (9.7%), formaldehyde (8.4%) and rubber accelerators (7.5%). Tea tree oil (5.7%) was the most common positive allergen in the facial series, and benzalkonium chloride (5.7%) the most common medicament allergen. Final clinical outcomes were allergic contact dermatitis (64.6%, n = 146), combined allergic/irritant dermatitis (6.2%, n = 14) and irritant dermatitis (4.9%, n = 11). Hand dermatitis was notable among hospital workers, users of cleaning product, hairdressers and nail technicians. History of atopic dermatitis was present in 25.6% (41 of 160) of patients with positive results. Among patients with allergic contact dermatitis, 28.1% were discharged, 50.0% were followed up and 21.9% were placed on see on symptoms (SOS) or patient-initiated follow-up (PIFU). The low re-presentation rate among patients on SOS or PIFU (20%) suggests effective symptom control following allergen avoidance. This study highlights the high diagnostic yield of patch testing and identifies metals, fragrances and preservatives as leading allergens, aligning with existing literature. The face and hands were the most commonly affected sites, reinforcing allergic contact dermatitis as a likely cause of dermatitis in these high-impact areas.