A 10-year-old boy presented with a rash that developed 2 days earlier on his lower extremities and then spread to his buttocks, abdomen, back, and arms (Figure 1). It was not present on his feet, hands, or face. The patient reported pruritus and said that some areas of rash were painful. He did not have a fever or any other symptoms.

His mother reported no recent changes in detergent, body wash, or soap. She was concerned about cases of hand-foot-and-mouth disease at her son's school. She said that he had spent time in their hot tub recently, but it had been cleaned thoroughly before use. The patient's mother and father developed similar rashes 1 day after their son's rash appeared.

QUESTION

Based on the patient's history and physical examination, which one of the following is the most likely diagnosis?

• A. Chickenpox.

• B. Fifth disease.

• C. Hand-foot-and-mouth disease.

• D. Hot tub folliculitis.

• E. Tinea corporis.

DISCUSSION

The answer is D: hot tub folliculitis, a skin infection of the hair follicles associated with soaking in a hot tub. Children are more susceptible to the condition than adults. Hot tub folliculitis develops after exposure to Pseudomonas aeruginosa in warm, wet areas such as inadequately chlorinated hot tubs or swimming pools.¹