Allergic contact dermatitis to salicylic acid: A case series of relevant sensitization.

Introduction: Allergic contact dermatitis (ACD) to salicylic acid (SA) is widely unreported. Furthermore, cross-reactivity between SA and other salicylates has not been reported despite well-documented in-group salicylate cross-reactivity.

Objective: To describe our clinic's experience patch testing to SA, highlighting seven cases of relevant reactions and concomitant reactivity with other salicylates.

Methods: Results of patch testing to 5% SA in petrolatum between 1 January 2020, and 9 February 2024, are reported. Seven cases of relevant reactions to SA are detailed.

Results: A total of 489 patients (27.5%) were tested to SA, 21 of which were positive: 7 doubtful (+/-), 14 weak positive (+), and no strong/extreme positive reactions. Four irritant reactions were documented. Of the 14 weak positive (+) reactions, 7 had definite or probable clinical relevance, 5 of which also reacted to other salicylates.

Conclusions: ACD to SA is likely underreported due to a lack of testing. In our experience, testing SA 5% petrolatum is tolerable without significant irritation. Cross-reactivity between SA and other salicylates is probable. Though SA appears to be the primary sensitizer in some cases, more studies are needed to understand its possible role as a marker for salicylate allergy.