What Caused this Pruritic Eruption?

A 33-year-old woman first noticed a pruritic eruption on her ears and the adjacent skin of her neck 2 days ago. She denies the use of new hair care products and exposure to any contactants.

Your plan of action is to:

A. Use new shampoo.

B. Use new conditioner.

C. Change new perfume.

D. Use new detergent.

E. Use new fabric softener.

(Answer on next page)

Answer: Contact dermatitis to shampoo

All the recommendations have merit, although in this case the patient’s shampoo, A, is the culprit. Often a manufacturer will change ingredients without printing a warning on the label.

Patch tests or trial and error will reveal the culprit. Because the lesions were close to the hair, we eliminated the patient’s shampoo first. The eruptions and pruritus began to resolve within a short period.