Contact Dermatitis Tests

Written by The Healthline Editorial Team & Jaime Herndon | Published on September 15, 2014
Medically Reviewed by George Krucik, MD, MBA on September 15, 2014

Tests for Contact Dermatitis

Contact dermatitis is a skin condition in which the skin reacts to an allergen or irritant by developing a rash. There is usually no test required for diagnosing the condition. It can be diagnosed by clinical observation and medical and social history. In some instances, tests can be helpful and necessary.

Patch Test

A patch test can be used in diagnosing allergic contact dermatitis. It helps determine which allergen is causing a skin reaction. It usually takes five to seven days for patch testing to be completed.

For a patch test, a doctor applies tiny amounts of different allergens directly to the patient’s back and covers them with a dressing that keeps the air out, or uses small wells and aluminum patches that are taped to the back.

In both methods, the patches are removed after two days and then reapplied and removed again after five to seven days. A reaction will indicate an allergen. Reactions can include a rash, bumps, or blisters. If the reaction disappears after the allergen is removed, the test was likely positive.

Bringing suspected materials to your doctor’s appointment can speed up the process. Ask your doctor if you should bring anything to your appointment.

Skin Biopsy

A skin biopsy is usually not done to diagnose contact dermatitis. It’s used to rule out anything else your doctor might suspect, like a fungal infection. Repeated and severe cases of contact dermatitis might prompt your doctor to perform a skin biopsy. This involves taking a sample of skin and sending it to a lab for testing.

If you have lesions the doctor may take a small sample from the sore or another area of skin. The sample is usually collected in one of three ways.

Shave Biopsy

This is the least invasive type of biopsy. It involves a doctor removing skin from the outermost layer. No stitches are needed.

Punch Biopsy

A doctor takes a pencil eraser-sized sample of skin using a sharp, hollow instrument. Stitches may be needed, depending on the size of the sample.

Excisional Biopsy

This is less common than the other types of biopsies. During this procedure, a doctor surgically removes the entire lesion and closes the wound with stitches. For large sections, a skin graft may be needed. 

Outlook

Most of the time, you will not need a test to diagnose contact dermatitis. Your doctor will be able to identify it from the history you give and an examination of the rash and surrounding skin. These tests are to make sure it’s not something other than contact dermatitis, or to identify a particular allergen. Talk with your doctor about whether testing is necessary and what would be the most appropriate choice. 

Was this article helpful? Yes No

Send us your feedback

Thank you.

Your message has been sent.

We're sorry, an error occurred.

We are unable to collect your feedback at this time. However, your feedback is important to us. Please try again later.

Trending Now

Numbness, Muscle Pain and Other RA Symptoms
Numbness, Muscle Pain and Other RA Symptoms
The symptoms of RA are more than just joint pain and stiffness. Common symptoms include loss of feeling, muscle pain, and more. Learn more in this slideshow.
Understanding the Progression of Ankylosing Spondylitis
Understanding the Progression of Ankylosing Spondylitis
One serious potential cause of back pain is ankylosing spondylitis. Get an understanding of what this condition is, how it progresses, and potential complications in this slideshow.
Common Asthma Triggers and How to Avoid Them
Common Asthma Triggers and How to Avoid Them
Learn about some of the most common triggers for asthma, as well as measures you can take to minimize your risk of exposure, symptoms, and flares.
How to Evaluate Your Multiple Sclerosis Treatment Plan
How to Evaluate Your Multiple Sclerosis Treatment Plan
Every multiple sclerosis (MS) patient is different, and no single treatment plan works for everyone. Learn more about what to consider when evaluating your MS treatment plan.
Migraine vs. Chronic Migraine: What Are the Differences?
Migraine vs. Chronic Migraine: What Are the Differences?
There is not just one type of migraine. Chronic migraine is one subtype of migraine. Understand what sets these two conditions apart.
Advertisement
Advertisement
Advertisement