A 33-year-old woman with sore red lips

Case scenario

A healthy 33-year-old woman presents with a three-month history of dry, sore, red and sometimes very flaky lips. She is allergic only to penicillin, takes no medications, and reports no recent changes in diet or cosmetic use. She regularly uses various lipbalms containing sunscreens and wonders if these are exacerbating the problem, although she has used these for many years. She has rarely worn lipstick since the problem began. On examination, the lips are swollen and erythematous, which extend beyond the outer margin (Figure).

Marked improvement occurs with use of an antibiotic and corticosteroid ointment, but the problem returns within days of ceasing treatment. Is allergy to a lipbalm component likely? How should I proceed?