Case: Dermatology #4
Case Study: Dermatology Cases for Primary Care
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“I’ve just come back from a 3-week African safari and I have a bad rash. I’m worried that I’ve caught a rare disease…”
Case #4: Steve is 30-year-old man from Seattle who was on 3-week African safari. While there, he developed a pruritic rash on his neck, back and waistline area. He describes the itching as ‘stinging’ and intermittent, being most noticeable in the late afternoon and associated with heavy sweating under the tropical sun. Following the episodes of pruritus, he noted decreased sweating at the sites of involvement. He continues to experience pruritis along the affected areas. He comes in today for evaluation.
Social History: Works as a land surveyor and spends much time outdoors. Very physically active and travels to foreign destinations 3 to 4 times per year. He returned yesterday from Africa, where he was outside in temperatures of 100 degrees Fahrenheit and high humidity for 8 to 10 hours per day. He was very careful to use insect repellant and does not recall being exposed to an insect or animal bite. Drank only bottled water and took all meals in restaurants. No prior history of skin rashes or urticaria.
Fit, suntanned man in no acute distress.
Height: 73”, weight 198 lbs, BP 128/69, temperature 98.7.
Review of Systems: Unremarkable
Skin: Multiple 2 to 4 mm, nonfollicular, erythematous papules with a central vesicle on the sides of the neck, upper back and the abdomen at the waistline area.
How would you proceed?
Published on May 31, 2010
Updated on June 7, 2010
Steve’s recent trip to a hot and humid climate indicates that miliaria rubris (heat rash or prickly heat) is likely the source of his symptoms. Heat rash is caused by excessive sweating and causes the sweat glands to become occluded with dead epithelial cells or bacteria. This initiates an immune response, which results in the subsequent skin rash. As the condition progresses into deeper layers of the skin, patients may begin to note a prickly or “pins and needles” feeling.
Steve should be reassured that this rash is likely a result of prolonged exposure to heat and humidity on his recent trip. Washing regularly will help to remove salt and bacteria from the skin, particularly when he is outdoors in a hot/humid environment. Cornstarch and other absorbent powders may also be used to absorb sweat and reduce moisture to prevent further inflammation. Moisturizers such as anhydrous lanolin may both prevent and treat heat rash.
Pruritus is a common symptom of heat rash. Menthol- and pramoxine-containing lotions reduce the itchiness, possibly by depressing cutaneous sensory receptors. Calamine lotion is also effective as it contains zinc oxide, which can have a drying effect. For more severe cases, or where first-line treatments are not effective, a mid-potency topical corticosteroid may be used.