Diagnosing Eczema

Reviewed by: HU Medical Review Board | Last reviewed: May 2024 | Last updated: May 2024

Living with eczema, also known as atopic dermatitis (AD), can be uncomfortable, painful, and frustrating. Getting an accurate diagnosis is the best way to start getting relief from symptoms.1

How is eczema diagnosed?

Healthcare providers diagnose eczema based on current and past symptoms, as well as the pattern of those symptoms. Often, eczema causes red, itchy, and inflamed patches of skin. These patches can appear anywhere on the body and may come and go.1

But eczema does not look the same on everyone. And the severity differs, too. Some people have redness, dry skin, and itchiness. Others have papules, blisters, or weepy skin. Over time, some people with eczema may develop thickened skin.1

Who diagnoses eczema?

Eczema can be diagnosed by various healthcare providers, including:2,3

  • Dermatologists
  • Pediatricians
  • Allergists
  • Primary care doctors

What happens during an eczema diagnosis?

During an eczema diagnosis, your doctor will examine your skin closely. They will pay attention to the appearance and location of any rashes or lesions. They also will ask about your:2,3

  • Medical history
  • Any previous skin conditions
  • Allergies you have or have had in the past
  • Family history of eczema
  • Other allergic conditions (food allergies, etc.)

Be prepared to discuss any symptoms you have had, including when they first appeared and whether anything seems to trigger or worsen them.2,3

Diagnostic criteria and guidelines

The American Academy of Dermatology (AAD) has provided guidelines to help healthcare providers diagnose eczema. According to the AAD, the following features must be present to diagnose a skin condition as eczema:1

  • Itching
  • Inflamed skin
  • Symptoms that follow a pattern – for example, those that appear in specific areas like the scalp or inner creases of the elbows or knees

Other important features that doctors consider in the diagnosis of eczema are:1

  • Age of onset
  • History of allergies
  • Family history of eczema or other allergies

These guidelines help doctors rule out other skin conditions, like:4

  • Scabies
  • Seborrheic dermatitis
  • Contact dermatitis (irritant or allergic)
  • Psoriasis

What tests can help diagnose eczema?

There are no tests that can definitively diagnose eczema. So, most diagnoses are made through observation of the signs and symptoms, as well as the person’s medical history.1

In unclear cases, doctors may perform a biopsy on the affected skin. This is a procedure in which a small sample of the skin is removed and examined under a microscope. It can show microscopic evidence of eczema and help doctors rule out other skin conditions.2,3

In some cases, doctors may perform other tests. Again, this is mostly to rule out other conditions. These tests include:1-3

  • Skin prick test – This involves applying small amounts of common allergens to the skin to see if they trigger an allergic reaction. While eczema is not always caused by allergies, identifying and avoiding triggers can help some people manage symptoms.
  • Patch testing – Patch tests use patches containing allergens that are placed on the skin and worn for 48 hours. Patch tests help detect allergic contact dermatitis, which causes a delayed allergic reaction to the skin.
  • Blood tests – Blood tests can check for elevated levels of certain antibodies or to assess the overall health of the immune system.

It is worth noting that the AAD does not recommend skin prick or blood tests for the routine evaluation of eczema.1

The role of allergy testing

People with eczema have a higher rate of environmental and food allergies than those without eczema. Healthcare providers ask about these conditions when they take a medical history. People who have allergy symptoms or whose eczema is persistent or difficult to treat may receive additional testing for allergens.1,2

Allergy testing can be valuable in diagnosing eczema, especially when allergies seem to trigger flare-ups. But not all eczema is caused by allergies. And allergy testing may not be right for everyone. Your doctor will determine whether allergy testing is right for you based on your symptoms and medical history.1,2

Don’t wait to have your skin symptoms assessed

Getting an eczema diagnosis can be a relief for many people with unexplained skin problems. If you are experiencing skin issues that do not go away, talk to a healthcare provider. With the right diagnosis and treatment plan, eczema is manageable.

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