You are here

Contact Dermatitis

Contact dermatitis is a broad term that refers to red, scaly, and itchy skin that is caused when some kind of substance contacts your skin and causes irritation. Contact dermatitis is generally divided into two kinds:

  • Irritant contact dermatitis results from direct damage to the skin layers by physical or chemical irritants (e.g., solvents, soaps, acids, bases).
  • Allergic contact dermatitis is caused by your body’s immune system reacting to chemicals that can be allergenic (e.g., poison ivy, cosmetic products, jewelry, baby wipes).

There are over 3,000 chemicals that have been reported to cause allergic contact dermatitis, and there are thousands more that can cause irritant contact dermatitis.

How Is Contact Dermatitis Diagnosed?

You’ll receive a thorough intake history before an extensive and customized panel of patch test allergens are applied to your back.

Patch testing is designed to determine if your rash is caused by an allergy to chemicals (whether they are natural or man-made) that come in contact with your skin. This test is not the same as the pinprick test or blood test that is typically performed by an allergist/immunologist.

What to Know for Your Appointment

Prior to patch testing:

  • Do not tan or receive phototherapy for two weeks before your appointment.
  • Stop using topical steroids on your back (everywhere else is OK) for one week before your appointment.
  • Don’t receive injection steroids (e.g., kenalog) for one month before your appointment.
  • Don’t take oral steroids (e.g., prednisone) for two weeks (unless explicitly directed by your physician).

We may need to reschedule your appointment if your back has significant body surface area covered by rash.


In general, 90 or more patches are secured with hypoallergenic tape to your back. The patch test procedure lasts for the duration of a little under a week, and during this time, the back can’t get wet.

On the final day of the procedure, the patch test results are obtained, and information about each positive allergen is provided. We’ll review which products are likely to be causing your rash, and we’ll work together to devise a management plan.

Contact Dermatitis Treatment

While there are a variety of prescription topical or systemic medications that can improve the symptoms of contact dermatitis, the best (and safest) treatment for contact dermatitis is to avoid the allergic or irritant substance.

How Long Does Contact Dermatitis Last?

Contact dermatitis can continue indefinitely with regular exposure to allergic substances.  Complete avoidance of the allergic substance will lead to recovery of the skin, but in some cases, even with complete avoidance, it can take up to a month or longer for the immune system to calm down and lead to resolution.

Can Contact Dermatitis be Prevented?

You can develop new allergies at any point in your life. Once an allergy has developed, contact dermatitis is best prevented by using patch testing to identify the substances to which you are allergic. With this knowledge, you will be able to prevent or minimize exposure to the chemicals that would otherwise trigger a rash.

Research and Advancing Care

We also perform research at the Contact Dermatitis Research Center. We’re actively recruiting patients for research studies using patch test allergens and single-cell sequencing techniques to better understand how contact dermatitis occurs. In doing so, we identify molecular targets to prevent symptoms or hasten resolution.