health

A primary care doctor will usually base the diagnosis by looking at the
patient’s skin, together with taking a personal and family history of allergies,
hay fever, and skin disorders. The patient may be referred to a dermatologist
(a doctor who specializes in disorders of the skin) to rule out the possibility
that the rash or skin irritation is caused by other diseases. The dermatologist
may take a skin biopsy in order to exclude other causes.
Swimmer’s itch can be a challenge to diagnose because there are no tests
specific for the parasites that cause it,andthe rash looks a lot like poison ivy or
chickenpox. In many cases the only clue is that the patient went swimming
within the past few days.
For contact dermatitis, the doctor may perform a patch test in order to
identify the specific substance(s) causing the rash. Small quantities of suspected
allergens or irritants in individual containers or patches are applied
to the skin of the patient’s back. The patches are covered with special nonallergenic
adhesive tape for forty-eight hours and then removed; the
patient’s skin is examined for blisters, swelling, or other reactions to the substances
in the patches.