The answer to a single question will help you diagnosis this rash

DermclinicA Photo Quiz to Hone Dermatologic Skills Case 2:This adolescent girl presents with a 1-week history of tender pustules on her trunk. Her primary care physician prescribed cloxacillin. Despite 4 days of therapy, there is no sign of resolution. The patient's answer to a single question will give you the diagnosis . . .   (Answer on next page.) Dermclinic—AnswerA "yes" to the question "Were you recently in a hot tub?" points to hot tub folliculitis. Case 2: This young girl has hot tub folliculitis. This is a common condition during the winter ski season when one of the popular après-ski events is to gather in a hot tub. Those who become infected usually present with a rash that starts within a few hours to a week after the hot tub experience. The lesions themselves may be tender to touch. There are usually large numbers of clustered erythematous papular pustules that are accentuated in the bathing suit area. The clinical clue is that these lesions usually have significant erythema with a very small pustule in the center of intense inflammation. A culture of the pustule and the single history question about hot tub exposure is generally sufficient to confirm the diagnosis. Pseudomonas aeruginosa is the responsible organism. It survives in hot tubs, especially those made of wood. It is particularly problematic when pH and chlorine levels are not closely regulated. It is not unusual for a majority of those who bathed in the hot tub to become infected. Many people have been infected at a single time by contaminated hot tubs at recreational centers and hotels. Otitis externa, pharyngitis, conjunctivitis, rhinitis, and mastitis have all been associated with the cutaneous infection. I advise owners of hot tubs to pay close attention to maintaining disinfectant levels, particularly if the water is kept at high temperatures. Once someone has become infected in a hot tub, I recommend that the tub be drained and all surfaces and tubing be wiped down with a bleach solution before the tub is refilled. The owner must then take meticulous care of the water to prevent recurrences. Hot tub folliculitis is usually self-limited, but persons with severe inflammatory disease or those with underlying immunosuppression should be treated systemically.  ■  (Go to Case 1.)