Pruritus, papules, and perspiration.

Background: The development of pruritus and papules with increased body temperature is a common clinical scenario seen in allergy practice, often leading to a diagnosis of cholinergic urticaria.

Objective: To describe an unusual case of miliaria and its significance in the evaluation of patients with pruritic papular eruptions that occur with increased body temperature.

Methods: An 18-year-old woman was referred to a local allergist for the evaluation of cholinergic urticaria. For the preceding 6 months, she had experienced a facial burning sensation along with diffuse pruritus accompanied by water-filled pinpoint bumps on her abdomen and extremities during exercise and with hot tub use. The lesions appeared anytime she exercised, and she reduced her workouts because of the associated discomfort. An exercise challenge was performed given the atypical description of her cutaneous symptoms.

Results: After indoor aerobic exercise on a treadmill, physical examination revealed facial flushing and numerous pinpoint translucent vesicles covering her abdomen. The diagnosis of miliaria crystallina was made. Given the intense pruritus she experienced with the lesions, she was prescribed cetirizine, 10 mg once daily. However, she noted no improvement with her exercise-induced miliaria. At follow-up 1 year later, her miliaria symptoms had spontaneously resolved with no sequelae observed.

Conclusion: Intermittent, pruritic, papular eruptions that occur with perspiration can provide a diagnostic challenge when not present on initial examination. Although this presentation often leads to a diagnosis of cholinergic urticaria, our case illustrates that other disorders must be considered in the differential diagnosis. In these situations, exercise challenge is a valuable adjunct.