This 10-year-old girl presents with a 2-week history of a persistent rash around the lips.

What are the important questions you need to ask to guide you to the correct diagnosis?

 Suspect oral hygiene and cosmetic products--including lip balms and gloss, lipstick, mouthwash, and toothpaste--as the cause of cheilitis. This girl has an

 allergic reaction to tartar-control toothpaste.

 The tartar-control agent was identified as the contactant. When the patient stopped using the toothpaste, the eruption resolved promptly.

A 14-year-old girl presents with this rash. It had been present for 2 months and is confined to the distal fingertips of both hands, which makes it uncomfortable for her to participate on the basketball team.

What do you suspect is the cause, and how would you treat the condition?

 This young patient was allergic to one of the ingredients in rubber basketballs, resulting in a

 The use of leather balls at practice and application of a topical corticosteroid alleviated the problem, and the girl was on the court once again.