Eczema (atopic dermatitis) diagnosis

The first step to managing moderate-to-severe eczema is diagnosis

Eczema (atopic dermatitis) symptoms like rashes or dry skin can resemble other skin conditions, making diagnosis tricky sometimes. An accurate diagnosis is crucial to ensure you receive the most effective treatment. Understanding the signs, triggers, and management strategies for eczema can help you take control of your symptoms and overall well-being.^1-3

How is eczema diagnosed?

While there is no single test to diagnose eczema, dermatologists do use specific criteria and guidelines to confirm it. The diagnosis is usually based on symptoms, medical history, and a physical exam.^2,3

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Physical examination

A dermatologist will carefully examine your skin, looking for common signs of eczema like redness, dryness, rash, and itchiness. They also assess the texture of your skin and the areas affected. If you have a rash, they will check the pattern and location. They’ll also note the frequency of your flare-ups, which can help determine the severity of your eczema.^1,4

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Medical history

Since having a family history of eczema is linked with diagnosis, a dermatologist will ask whether you, your parents, or any other family members have experience with^3,4:

Eczema
Hay fever
Other allergies

Your healthcare provider might also ask about your cosmetic and personal hygiene products, as some ingredients can be irritating and trigger eczema symptoms. This information helps doctors understand your condition better and tailor the treatment to your needs.⁴

What type of diagnostic testing identifies eczema?

Although there is no single diagnostic test for eczema (atopic dermatitis), some tests can help rule out other conditions such as psoriasis, skin infections, or allergic skin reactions. Other laboratory tests, like a blood test or skin swab, can inform more personalized and effective treatment strategies for eczema.^3,4

Allergy testing for eczema

Allergy testing can identify what triggers make your eczema worse, including certain foods, pets, or environmental factors like pollen or dust mites. A dermatologist or healthcare provider may perform a blood test, or most commonly, a patch test.^5,6

How does a patch test work?

A dermatologist will apply small amounts of common allergens to patches, which are then placed on the skin, usually on the back. The patches typically stay in place for 48 hours. The skin is checked a few days later to see which allergens caused reactions and are likely contributing to eczema.⁵

Skin biopsies for eczema

Although not always necessary, some tests like a skin biopsy may help support an eczema diagnosis or rule out other skin conditions. During a skin biopsy, a healthcare professional removes a small piece of skin and sends it to a laboratory for further tests. This is a relatively painless minor procedure that usually heals within a week.⁴

When should you see a dermatologist?

Consider speaking with a dermatologist if you are experiencing at least one of the following^1,7:

1

Severe symptoms: If you experience intense itching, widespread redness, or significant discomfort that interferes with daily activities or sleep

2

Signs of infection: If the affected skin becomes swollen, painful, or develops yellowish crusts, which could indicate an infection

3

Persistent symptoms: If your eczema (atopic dermatitis) does not improve with over-the-counter treatments or home care measures

4

Uncertain diagnosis: If you're unsure whether your symptoms are due to eczema or another skin condition

5

Impact on quality of life: If eczema is significantly affecting your mental health, causing stress, anxiety, or depression

A dermatologist can help you identify your unique triggers, discuss different eczema treatments, and ensure you get the best option for you. If you have any specific concerns or symptoms, it's always best to seek professional advice.³

Seeking management for eczema in adulthood

Although eczema is often identified and treated in early childhood, diagnosis of adult-onset eczema is important for prompt and proactive management. This helps your dermatologist better prevent symptoms from developing into a damaging itch-scratch cycle.^8,9

Not an actual patient.

Frequently Asked Questions

How is the severity of eczema evaluated?

The severity of eczema (atopic dermatitis) is determined based on a standardized scoring system. During your visit with a dermatologist, they will assess the extent of the affected area of your skin, the intensity of your symptoms (like intensity of the itch, redness, swelling, skin thickening and oozing), and your overall quality of life.⁹

Receiving treatment for eczema

From creams and lotions to prescription biologics, discover the treatments available for eczema today.

Eczema Treatment

References: 1. Purvis D. Guidelines for the diagnosis and assessment of eczema. DermNet. September 2014. Accessed March 24, 2025. https://dermnetnz.org/topics/guidelines-for-the-diagnosis-and-assessment-of-eczema 2. National Institute of Arthritis and Musculoskeletal and Skin Diseases. Atopic dermatitis: diagnosis, treatment, and steps to take. Accessed March 24, 2025. https://www.niams.nih.gov/health-topics/atopic-dermatitis/diagnosis-treatment-and-steps-to-take 3. National Eczema Association. Atopic dermatitis. Accessed March 24, 2025. https://nationaleczema.org/eczema/types-of-eczema/atopic-dermatitis 4. NYU Langone Health. Diagnosing eczema & dermatitis. Accessed March 24, 2025. https://nyulangone.org/conditions/eczema-dermatitis/diagnosis 5. Ludmann P. Patch testing can find what’s causing your rash. American Academy of Dermatology Association. Updated March 15, 2021. https://www.aad.org/public/diseases/eczema/types/contact-dermatitis/patch-testing-rash 6. National Health Service. Atopic eczema. Updated September 2024. Accessed March 24, 2025. https://www.nhs.uk/conditions/atopic-eczema 7. Ballard A. National Eczema Society. Staph & eczema: A skin-duo you need to know about. Updated November 28, 2022. Accessed March 24, 2025. https://nationaleczema.org/blog/staph-eczema-a-skin-duo-you-need-to-know-about 8. American Academy of Dermatology Association. Can you get eczema as an adult? Accessed March 24, 2025. https://www.aad.org/public/diseases/eczema/adult/can-get 9. Allergy Asthma Network. What is moderate to severe eczema? Accessed March 24, 2025. https://allergyasthmanetwork.org/what-is-eczema/moderate-to-severe-eczema 10. Coulson I. Patch tests. DermNet. December 2021. Accessed March 24, 2025. https://dermnetnz.org/topics/patch-tests 11. American Academy of Allergy, Asthma & Immunology. Allergen defined. Updated July 2024. Accessed March 24, 2025. https://www.aaaai.org/tools-for-the-public/allergy,-asthma-immunology-glossary/allergen-defined

Important Safety Information

Indications: NEMLUVIO^® (nemolizumab-ilto) is a prescription medicine used:

to treat adults and children 12 years of age and older with moderate-to-severe eczema (atopic dermatitis or AD) in combination with prescription therapies used on the skin (topical) when the eczema is not well controlled by topical therapies alone. It is not known if NEMLUVIO is safe and effective in children with atopic dermatitis under 12 years of age.
to treat adults with prurigo nodularis. It is not known if NEMLUVIO is safe and effective in children with prurigo nodularis under 18 years of age.

Do not take NEMLUVIO if you are allergic to nemolizumab-ilto or to any ingredients in NEMLUVIO. Before taking NEMLUVIO, tell your healthcare provider about all of your medical conditions, including if you:

are scheduled to receive any vaccination. You should not receive a live vaccine right before or during treatment with NEMLUVIO.
are pregnant or plan to become pregnant. It is not known whether NEMLUVIO will harm your unborn baby.
are breastfeeding or plan to breastfeed. It is not known whether NEMLUVIO passes into your breast milk and if it can harm your baby.

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

NEMLUVIO may cause serious side effects, including: allergic reactions (hypersensitivity). Stop using NEMLUVIO and tell your healthcare provider or get emergency help right away if you get any of the following symptoms:

Breathing problems or wheezing
Swelling of the face, lips, mouth, tongue, or throat
Fainting, dizziness, feeling lightheaded
Fast pulse
Swollen lymph nodes
Joint pain
Fever
Skin rash (red or rough skin)
Nausea or vomiting
General ill feeling
Cramps in your stomach area

The most common side effects of NEMLUVIO include:

Eczema: headache, joint pain, hives (itchy red rash or wheals), and muscle aches
Prurigo Nodularis: headache and skin rashes: atopic dermatitis (a type of eczema), eczema, and eczema nummular (scattered circular patches)

These are not all of the possible side effects of NEMLUVIO.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Please see full Prescribing Information, including Patient Information.