Patch Testing in an Allergy Clinic: Real-world Experience

Contact dermatitis is an inflammatory skin disorder characterized by an erythematous pruritic rash. The disorder can be either irritant or allergic. Allergic contact dermatitis is diagnosed by patch testing along with patient history.

To review the results of patch tests conducted thought 2 years and to present real-life data characterizing clinical features and comparing prevalent local allergens to the ones common worldwide.

The retrospective cohort included 517 participants (384 females and 133 males) who underwent patch testing during a 2-year period. For each patient, clinical and demographic data were collected, and statistical analysis was conducted.

We found that 261 patients had a positive test for at least one allergen. More females tested positive than males (52.9% vs. 43.6%). Test indications other than dermatitis were associated with a negative result. Hands, head, and neck were the most prevalent body parts affected. Patients with a background of atopic dermatitis had a higher rate of contact sensitization (69 vs. 43). Patients with a specific suspected offending allergen had significantly higher contact sensitizations. The most common allergen was nickel.

Patch testing should be conducted in patients with relevant dermatological findings accompanied by taking a thorough medical history. Clinicians should be updated on emerging allergens and exposure trends.