Atopic dermatitis refers to the skin condition that many people call eczema. It causes individuals to experience patches of dry, itchy skin that may crack, bleed, or become infected. Doctors further categorize atopic dermatitis into two subtypes based on the presence or absence of allergy.
Atopic dermatitis (AD) caused by an allergen is known as extrinsic AD, while intrinsic AD does not arise from an allergen. Some people may also refer to the two subtypes as allergic AD and nonallergic AD, respectively.
In this article, we will explain the difference between intrinsic and extrinsic AD. We will also discuss the symptoms and treatment of intrinsic AD.
Intrinsic AD refers to a subtype of AD that does not arise from an allergen. It is also known as nonallergic AD, nonatopic eczema, and nonallergic atopic eczema.
Both intrinsic and extrinsic AD present with similar symptoms, but people with intrinsic AD exhibit the normal level of immunoglobulin E (IgE) in their blood. IgE is an antibody produced by the immune system in response to an allergen. Intrinsic AD is not associated with other atopic conditions, such as asthma, hay fever, and food allergies.
Researchers previously identified a distinction between subtypes of asthma based on the presence or absence of allergens. Subsequently, doctors have applied the same distinction to AD based on the presence or absence of increased IgE and atopic disease.
The main difference between the two subtypes of AD is the cause of symptoms. Extrinsic AD is triggered by allergens, while intrinsic AD is not.
For this reason, a person with intrinsic AD has normal IgE antibody levels in their blood. Generally, they also do not have any other atopic conditions. Further differences between the two types of AD are listed below.
|Intrinsic (not triggered by allergens)||Extrinsic (triggered by allergens)|
|usually starts in adulthood||usually starts in childhood|
|less common and occurs more often in women||classical type with higher prevalence (more common)|
|tends to be milder||tends to be more severe|
|normal or low IgE blood levels||high IgE blood levels|
|regular skin barrier function||weakened skin barrier function (less hydration and higher water loss)|
|not associated with food allergies, allergic rhinitis, and asthma (atopic march)||associated with food allergies, allergic rhinitis, and asthma|
|negative skin patch or prick allergy testing to common allergens||positive skin patch or prick allergy testing to common allergens|
|not as prone to skin infections||prone to bacterial and fungal skin infections|
The exact cause of intrinsic AD is unknown. Evidence suggests it likely involves a combination of genetic mutations, an overactive immune system, and environmental factors that cause the skin to become dry, leading to damage and inflammation.
The symptoms of intrinsic and extrinsic AD are very similar and may include:
A healthcare professional can typically diagnose AD through a physical exam and a thorough personal and family history. They may also order an IgE antibody blood test and allergic skin testing to help determine the subtype of AD.
Although there is currently no cure for intrinsic AD, specific treatments can help control the condition. The goal of treatment is to:
- manage dry skin
- control itching
- prevent flare-ups and avoid triggers
- prevent secondary infections or complications
Depending on the severity of symptoms, treatment for intrinsic AD may involve a combination of the following therapies:
People with AD typically have dry skin that leads to itching, rashes, and thickened skin patches. Keeping the skin well hydrated and moisturized is an essential component of AD care. Doctors may advise people to take a lukewarm bath, gently pat themselves dry, then apply a moisturizer to seal in moisture.
According to the National Eczema Society, the most common medications used to treat eczema include:
- Topical treatments: These are creams or ointments that people apply directly to the skin to reduce inflammation. Some common topicals for AD include topical steroids.
- Oral medications: These are pills or capsules that people take by mouth that may help to control and slow AD symptoms by suppressing the immune system.
- Over-the-counter treatments: These options do not require a prescription and include pills and topicals, such as antihistamines and pain relievers.
- Prescription injectables (biologics): This type of therapy uses proteins that can stop or limit certain parts of the immune system response, reducing inflammation and symptoms of AD. Examples of biologics include dupilumab (Dupixent).
In some cases, people may use phototherapy to treat AD symptoms in adolescents and adults. Phototherapy uses UV light waves to suppress the body’s immune response. It may be a suitable and cost effective option for moderate to severe AD, especially if they do not respond to other treatment options.
Home remedies cannot cure AD, but the following may help relieve some symptoms:
- aloe vera gel
- coconut oil
- tea tree oil
- cool compresses
It may also be helpful for individuals to:
A person may want to speak with a doctor if they notice that their skin is often dry, itchy, and painful. Usually, people with intrinsic AD can manage it at home by keeping their skin hydrated, avoiding triggers, and using over-the-counter medications or prescriptions as recommended by a doctor.
People with AD are prone to skin infections that may require immediate attention. Symptoms of these infections include:
- a sudden worsening of eczema
- flu-like symptoms
- painful discolored skin
- severe insomnia or symptoms of depression
Intrinsic AD is a chronic skin condition that results in dry, itchy skin without the presence of an allergen or other atopic illness. The symptoms are similar to those of extrinsic AD, but the two types have different causes. Treatment typically involves following a good skin care routine and using topical or oral medications when necessary.