Allergic Contact Dermatitis of the Scalp: Dare to Look over that Imaginary "Fence"

Diagnosing Allergic Contact Dermatitis of the Scalp: Clues Lie Beyond the Scalp!

Allergic contact dermatitis (ACD) of the scalp can occur with many topical products.
Shampoos, conditioners, hair dyes are among the most common but the list of compounds that can cause allergic contact dermatitis is vastly large.

Affected patients often develop redness and scaling of the scalp.

About 70-80 % of patients with allergic contact dermatitis of the scalp also have rashes in other areas beyond the scalp. We refer to this as the “rinse off” area because the chemicals applied to the scalp may “rinse off” in the shower and affect other skin areas. These areas include the face, forehead, eyelids, neck, chest and ears.

When a practitioner thinks that they may be dealing with a possible allergic contact dermatitis of the scalp it’s critically important to ask questions about these “other areas”

Do you get rashes on the face or forehead?

Do you get rashes on the neck?

What about the eyelids?

What about the neck or chest?

What about the ears?

If one suspects allergic contact dermatitis then referral to a highly specialized dermatologist for patch testing is often the best step to take. If ACD is proven, one needs to avoid all topical products that contain the compound that was causing the allergy.

A helpful memory tool when evaluating possible allergic contact dermatitis of the scalp is to cue oneself to “look and think beyond the scalp” and ask really good questions about rashes on the face, ears, neck, chest and eyelids.

I tell the doctors and trainees I work with to use “look over the FENCE” as a helpful memory tool and reminder that valuable clues about allergic contact dermatitis are indeed found beyond the scalp. The five letters of “fence” spell out the key areas that are often impacted by allergic contact dermatitis: face, eyelids, neck, chest and ears.

In summary, don’t just keep looking at the scalp and thinking about the scalp if you want to properly evaluate for scalp allergic contact dermatitis - be brave and look over that imaginary fence for more clues!

The face, forehead, eyelids, neck, chest and ears often have clues waiting for the astute clinician.