Contact Dermatitis
By Rear Adm. Joyce Johnson, D.O., M.A.

What is contact dermatitis? How do I know if I have it?

Dermatitis means inflammation of the skin. Contact dermatitis is a skin rash that usually itches and might include bumps that ooze (vesicles), patches of redness or swelling, and crusting or scaling. It can be an allergic reaction or it can result from contact with some substance. 

Poison ivy is a good example of allergic contact dermatitis. On your first exposure, there is no obvious problem. However, that first exposure can set the body’s allergic response mechanism to making antibodies against the poison ivy. If you are exposed again, these antibodies begin the typical allergic skin response of oozing, itching lesions. 

Simple irritants range from strong acids to everyday soaps and detergents; what is an irritant to one person might not be a problem for another. More fragile skin areas, such as the face and eyelids, are more susceptible than tougher skin areas, such as the back of the arm. 

Chemicals found in aftershave lotions, sunscreens, cosmetics, perfumes, some topical medications, etcetera, may cause photoallergic or phototoxic contact dermatitis. This condition occurs when you apply the product to the skin and then expose the skin to the sun. 

There are many other causes of contact dermatitis. Metals such as nickel, found in some jewelry, can cause itchy earlobes (from earrings, especially those for pierced ears) or itchy fingers (from rings). 

Some of the dyes and chemicals used to tan leather also are problematic. An itchy area of contact dermatitis around the waist can result from a leather belt; itchy redness on the feet can result from leather sandals or slippers. Itchy, puffy eyes might result from eye makeup, creams, or contact lens solutions.

Symptomatic management of contact dermatitis may include topical steroids or, rarely, systemic steriods. Antihistamines can reduce itching. Lasting treatment and prevention include removing the offending substance, but identifying it is the first and most difficult part.

A patient’s history and “out of the box” thinking are key to diagnosing contact dermatitis and often solve the mystery of an unexplained rash. For example, a teenage boy was diagnosed and treated for athlete’s foot; he carefully used a range of creams and salves for more than a year to no avail. Finally, suspecting contact dermatitis, his mother washed all his socks inside out with nothing but some chlorine bleach. Within a couple of weeks, the peeling, itchy skin on the soles disappeared and his feet were back to normal.