The chemical components of disposable facemasks can cause allergic and irritant skin reactions, and patch tests are key to making the correct diagnosis, say clinicians from South Korea.

Dr Hye One Kim and colleagues from the dermatology department at Kangnam Sacred Heart Hospital in Seoul did a case-control study of adults diagnosed with facial dermatitis after the COVID-19 outbreak.

Participants included 27 patients whose lesions and symptoms worsened after wearing a disposable mask, and 70 control patients who developed facial dermatitis due to other causes.

Patients in the mask group had clinical dermatitis symptoms for a significantly shorter time (mean duration six months) than patients in the control group (mean duration 23 months), the researchers report in the Journal of the American Academy of Dermatology.