Atopic dermatitis is a type of eczema, which causes dryness, itchiness, rashes, and other skin lesions. However, it covers several types of eczema and skin inflammation, such as contact dermatitis, discoid eczema, and dyshidrotic eczema. Atopic eczema and eczema are often used interchangeably, but there is a subtle difference between the two terms:
- Eczema: Eczema is a broad term used to describe a group of skin conditions characterized by red, itchy, and inflamed skin. It is a general term that encompasses various types of dermatitis, which is inflammation of the skin. There are several types of eczema, and atopic eczema is one of them. Other types of eczema include contact dermatitis (caused by contact with irritants or allergens), seborrheic dermatitis (affecting areas rich in sebaceous glands, such as the scalp), and nummular eczema (manifesting as coin-shaped patches).
- Atopic Eczema (Atopic Dermatitis): Atopic eczema is a specific type of eczema that is characterized by chronic and inflammatory skin symptoms, such as itching, redness, and rash. It is a chronic and relapsing condition that often begins in infancy or childhood and is associated with other allergic conditions, such as asthma and hay fever. Atopic eczema has a strong genetic component, and individuals with a family history of atopic diseases are more likely to develop it. It is considered one of the most common and well-known types of eczema.
Eczema refers to a group of conditions that cause the skin to become itchy, inflamed, or have a rash-like appearance. Evidence suggests that more than 31 million people in the United States are affected by eczema, with atopic dermatitis being the most common type.
This article defines eczema and atopic dermatitis and discusses other types of eczema, including how to identify, treat, and prevent them.
Definitions of terms
Both dermatitis and eczema are umbrella terms that people may use to refer to conditions that cause inflamed, irritated, and often itchy skin. There are many different types of eczema, such as neurodermatitis, stasis dermatitis, and atopic dermatitis (AD).
AD is a condition that makes the skin itchy and dry. The term atopic refers to being prone to developing an allergic hypersensitivity reaction to a trigger. AD is the most common type of eczema, which is why many people often simply call it eczema. Evidence suggests it affects roughly 1–3% of adults and 15–20% of children worldwide.
AD is a chronic skin condition that may come and go and currently has no cure. It has associations with other atopic conditions such as hay fever and asthma. In AD, a combinationTrusted Source of genetic, immune system, and environmental factors likely cause the skin to experience inflammation against typically harmless substances in the environment.
Other types of eczema
Other types of eczema can include the below.
Asteatotic eczema
Like AD, asteatotic eczema, also known as eczema craquelé or xerotic eczema, has associations with dry skin. However, most skin lesions in asteatotic eczema are in the legs and look like plates of dry skin separated by cracks, showing a distinctive “dry riverbed” appearance. This type of eczema is typically more common in older adults, likely due to skin changes associated with aging.
Contact dermatitis
AD and contact dermatitis go through the three stages of eczema and show similar features. However, with contact dermatitis, a person’s skin experiences irritation or an allergic reaction after contact with a trigger, causing the skin to sting, burn, and become inflamed.
There are many known potential irritants, including hair dyes, nickel, certain antibiotics, preservatives, and chemicals. There are two types of contact dermatitis: irritant and allergic contact dermatitis.
Discoid or nummular dermatitis
Similar to AD, discoid or nummular dermatitis is a long-term condition. It presents with similar symptoms of itchy patches of skin that may sometimes ooze fluid. However, in discoid dermatitis, skin patches have a distinct round shape.
Common triggers can include dry skin, insect bites, chemical burns, and other skin trauma. People with AD and allergic contact dermatitis are also prone to developing discoid eczema.
Dyshidrotic eczema
Dyshidrotic eczema, which some health experts call pompholyx, causes small, itchy, and painful blisters to develop on the soles of the feet and palms of the hand.
Similar to AD, this condition tends to run in families. Dyshidrotic eczema is more common in adults aged under 40 years and females. Some people only have a single flare-up, but a majority can have it over the long term. Common triggers may include allergies, hot weather, moist hands, stress, and exposure to metals.
Neurodermatitis
While AD and neurodermatitis can result in itchy lesions, skin thickening (lichenification), and discoloration, lesions in neurodermatitis are usually limited to one or two patches of skin. Itchy patches can develop anywhere but commonly appear on the feet, ankles, wrists, elbows, scalp, back of the neck, and groin area.
Neurodermatitis, which doctors call lichen simplex chronicus, develops when a person scratches an itchy skin patch. These lesions are often very itchy, while scratching may cause bleeding and scarring.
Seborrheic dermatitis
Seborrheic dermatitis affects skin areas that produce a lot of oil, including the scalp, nose, and upper back. The skin can appear swollen and greasy, while crusty scales may appear. The skin condition is due to an overproduction of Malassezia yeast, which causes an overreactive immune response, leading to skin inflammation.
It can occur in infants, known as cradle cap, and in adults. In infants, it often resolves by itself and does not come back. However, it often persists in adults and may come and go.
Varicose or stasis dermatitis
Also called stasis dermatitis, venous eczema, and gravitational dermatitis, this condition usually affects people with reduced circulation. While it is more common in older adults and women, it can also occur in young people with a predisposition to developing varicose veins. Aside from varicose veins, an individual with this skin disorder may notice ankle swelling and skin discoloration due to blood vessel bursting. It can also cause ulcers.
How to identify
Since all eczema types commonly present with symptoms, such as skin dryness and inflammation, it can be challenging to differentiate. However, each type has its differences, which are below.
Age
AD most often affects young children and infants, with the majority occurring in those aged 1 to 5 years of age. In contrast, other types may occur at any age but are typically more prevalent in adults.
Type of lesion
While most types have similarskin lesions, others have distinct characteristics. Discoid eczema has a distinctive round shape, while dyshidrotic eczema often comes with small, painful blisters. Contact dermatitis lesions typically appear in the area exposed to the irritant and have clear visible borders.
Location
In infants and young children, AD lesions are typically present on the cheeks or the creases of elbows and knees, while adults often have AD around their eyes. Similarly, skin lesions in other types occur in other areas. Asteatotic and varicose eczemas have lower body lesions, dyshidrotic eczema affects the soles and palms, and seborrheic eczema most often affects the scalp.
Tests
Blood tests may reveal atypical immunoglobulin E levels for people with extrinsic AD, while these levels may be standard in other types of eczema. Patch testing can identify irritants in contact dermatitis, and doctors may detect reduced blood flow in people with varicose eczema.
Comorbidities
AD often occurs with other atopic conditions. A 2021 review states asthma is a common comorbidity in people with AD. Additionally, individuals with varicose eczema have reduced circulation and may indicate heart and kidney problems.
In summary, eczema is a general term that refers to a group of skin conditions with similar characteristics, while atopic eczema specifically refers to a type of eczema with a genetic predisposition and an association with other allergic conditions. Atopic eczema is a subset of eczema, and when people commonly refer to “eczema,” they are often referring to atopic eczema due to its prevalence and recognition as a prominent form of the condition.