Allergic contact dermatitis to topical medicaments: Revisited.

Background: Allergic reaction to topical drugs varies depending on use and availability of topical drugs and self-medication.

Objective: We aimed to determine the incidence of contact dermatitis to topical medicaments among patients referred for patch testing.

Methods: All patients with suspected allergic contact dermatitis were patch tested with standard and medicament series. The characterization was performed according to the MOAHLFA index.

Results: 59/215 (27.4%) patients had positive reactions to at least 1 medicament but only 13/59 (22.0%) had a relevant history. The 3 most common positive medicaments were framycetin 23/215 (10.7%), miconazole 22/215 (10.2%), and econazole 17/215 (7.9%). Among those positive to medicament, face was the most common location 22/59 (37.3%). 39/215 (18.1%) had more than 2 co-positive standard allergens and showed significant higher rate of topical medicament sensitization. The contributing factors of medicament allergy were the history of suspected allergens in personal care products (OR = 2.09, P = 0.038), topical drugs (OR = 2.93, P = 0.002), topical treatment (OR = 2.47, P = 0.011), and history of drug allergy (OR = 1.78, P = 0.023).

Conclusions: The study showed a high rate of medicament sensitization especially antibiotic and antifungal drugs. The incidence of positive medicament patch test result was associated with facial dermatitis. Polysensitization and history of previous exposure, either as treatment or overusing of drugs, significantly associated with medicament positive patients. This study supports the inclusion of medicaments within the standard series of patch test.