“Intrinsic eczema” is a term referring to atopic dermatitis (AD) that isn’t related to genetics, allergies, or other common causes of this skin condition.

It’s estimated that between 10 and 40 percent of people with AD have this type of eczema, according to a 2015 research review, and it mostly affects women.

Learn more about what it means to have intrinsic eczema and why it’s difficult, without a doctor’s diagnosis, to tell the symptoms apart from allergic eczema.

“Intrinsic eczema” is a medical term used by some skin professionals to describe a type of eczema that isn’t related to criteria commonly seen in this skin disease, per 2015 research. These criteria include:

The terms “intrinsic” and “extrinsic” were first used to distinguish between allergic and nonallergic sources of asthma, respectively. However, describing eczema as intrinsic or extrinsic remains controversial among professionals because it can lead to confusion.

Intrinsic vs. extrinsic eczema

While intrinsic eczema means that an individual with AD does not have elevated IgE levels and related atopic disorders, extrinsic eczema indicates the opposite.

If an allergist or dermatologist describes your eczema as extrinsic, you likely have a genetic predisposition, allergies, or asthma. Extrinsic eczema is also sometimes called allergic AD, and it’s the most common type, per 2010 research.

Eczema itself is an inflammatory skin condition marked by patches of rashes that are red to brown in color and extremely itchy, especially at night. If you scratch these patches, they can become infected.

While you may develop eczema anywhere, it tends to occur most commonly in the following areas:

  • on the hands
  • around the knees
  • on the elbows
  • on the scalp
  • on the cheeks (in infants)

Both intrinsic and extrinsic eczema have similar symptoms. However, unlike extrinsic eczema, intrinsic (nonallergic) forms tend to cause milder symptoms. Aside from red skin rashes, people with intrinsic eczema may also have Dennie-Morgan lines under their eyes.

Also, while extrinsic eczema can result in an atypical skin barrier, intrinsic eczema has not been found to cause these concerns, according to the 2010 research mentioned earlier.

People with extrinsic forms of eczema are also more likely to have sensitive skin than those with intrinsic eczema, 2018 research suggests.

If you have sensitive skin, you may experience worsening eczema symptoms when you come into contact with:

  • products containing dyes, such as detergents
  • preservatives
  • fragrances
  • harsh soaps

A healthcare professional generally diagnoses intrinsic eczema with a physical exam.

If you have a history of allergies along with chronic eczema, your doctor may refer you to a specialist, such as an allergist or immunologist. They might conduct allergy testing to determine which allergens may lead to eczema, hay fever, and other related conditions.

Keep in mind that intrinsic eczema is not related to allergies, though. If allergies are suspected as a cause of your eczema, then you likely have the extrinsic type.

Extrinsic eczema may be treated with both topical solutions and allergy medications, but intrinsic eczema is managed with topical treatments only. These may include:

  • moisturizers
  • emollients
  • over-the-counter or prescription steroid ointments

Avoiding your triggers can also help you manage intrinsic eczema. For example, if you find that certain skin care products, clothing, or foods cause rashes, it’s best to avoid these items. An allergist or immunologist may also help you identify substances you could be sensitive to.

Other steps that can help alleviate and prevent eczema rashes include:

  • Avoid bathing in hot water.
  • Take daily lukewarm showers or baths.
  • Apply moisturizer within 5 minutes after bathing.
  • Rinse your skin off in the shower immediately after swimming.
  • Avoid extremely cold or hot temperatures.
  • Use a humidifier during dry months.
  • Wear loose-fitting, cotton-based fabrics only.

While the exact causes of intrinsic eczema are unknown, the two primary characteristics that healthcare professionals use to make a diagnosis are a typical IgE level combined with a lack of other atopic conditions, such as asthma and allergies.

In general, eczema tends to run in families, according to the American Academy of Dermatology, especially if there’s a history of atopic diseases. Your immune system may also play a role by causing your body to overreact in response to everyday substances.

Since intrinsic eczema is not caused by allergies, it’s not possible to have allergic intrinsic eczema. If your skin condition is thought to be caused by allergies, you likely have extrinsic eczema.

All types of atopic eczema can cause symptoms to come and go in cycles. Even with intrinsic eczema, you should be prepared for your rashes to get better and then come back, particularly if you come into contact with any of your triggers.

It may also take time to figure out which topical lotions or medications work best for your skin. Keep this in mind as you work with your doctor to determine the best intrinsic eczema treatments for you.

Intrinsic eczema is a type of atopic dermatitis that develops with typical IgE levels, as well as without commonly co-occurring atopic conditions, such as hay fever and asthma.

It’s also sometimes called nonallergic eczema. People with extrinsic — or allergic — eczema do have elevated IgE serum levels, and they are at a greater risk of developing allergies or asthma.

Despite these differences, many of the telltale symptoms, such as extremely itchy rashes, occur in both intrinsic and extrinsic eczema. You can manage and treat these symptoms the same way, regardless of which type of eczema you have.

Whether your AD is considered intrinsic or extrinsic, it’s important to talk with your doctor about any symptoms you’re having and whether they’re improving with your current treatment plan.