How Age Affects the Location of Eczema Rashes

Eczema appears where you can scratch the itch

Baby with eczema at the doctor
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The most common form of eczema is atopic dermatitis, which usually has a red, itchy rash. This type of eczema mostly affects people who tend to have asthma, hay fever, or food allergies. In addition, many experts believe there is a genetic predisposition to developing it.

The location of atopic eczema rashes is predictable, depending on the age of the person. This is because the rash will show up where that person has scratched an itch, and those are predictable locations for babies, toddlers, children, and adults.

Areas affected by eczema are typically very itchy, dry, crusty, scaly, and/or thickened. In addition, these areas may cause skin discoloration, causing the skin to become lighter or darker, depending on your pigmentation.

Location of Eczema Depends on Age

With other kinds of rashes, the rash comes first, then it feels itchy. Instead, atopic dermatitis is an itch that, when scratched, erupts into the identifiable eczema rash. Therefore, for a person who has atopic dermatitis, scratching any area of skin long enough will result in eczema. Here is how it typically appears, based on age:

  • Infants: In infants and very young children, eczema most often involves the face (especially the cheeks), chest, and back of the scalp. This distribution reflects where the child is able to scratch, and therefore usually spares the diaper area.
  • Toddlers: Eczema tends to reach a peak of intensity between ages of 2 and 4 years. During this time, it most commonly affects the skin in front of the elbows and behind the knees. These areas are known as "flexural areas." It can also begin to affect areas of the body, such as the lower legs and feet, that begin to come into contact with more surfaces as children become more mobile.
  • Older Children and Adults: In older children and adults, the location of eczema classically involves the skin in front of the elbows and behind the knees. Again, these “flexural areas” represent areas that are easily scratched once you are beyond your baby years.

While atopic dermatitis is usually considered a condition of childhood (typically appearing during the first year) and most people outgrow it by the time they are teenagers, it can persist into adulthood.

When this happens, it most often affects areas exposed to allergens or irritants such as the hands, scalp, eyelids, and nipples.

Treatment and Avoiding Itching Triggers

Treating eczema is aimed mostly at decreasing inflammation of the skin and avoiding known triggers such as allergens, rough surfaces, or extreme temperatures. Topical steroid creams and ointments are used to soothe the itchiness. In addition, maintaining optimal skin moisture can help prevent outbreaks and minimize the risk of infection. 

Itching of the skin can be caused by irritants, infections, allergies, and stress. Here are some of the common triggers:

  • Irritants: These cause itching through direct stimulation of the skin and include harsh soaps, chemicals, wool fabrics, heat, and sweating. You can avoid these irritants by using gentle soaps, wearing cotton clothing, and keeping cool and dry.
  • Infections: People with atopic dermatitis are more susceptible to skin infections by various bacteria, fungi, and viruses. Many people with eczema have large amounts of the common skin bacterium Staphylococcus aureus, which can worsen the itching and eczema. Herpes infections (similar to the kind that causes cold sores) and the virus responsible for chicken pox and shingles can also cause severe skin infections in people with atopic dermatitis.
  • Allergies: Allergens that come in direct contact with the skin, such as animal dander and dust mites, cause the most problems, although pollens and mold spores in the air can also worsen the condition. Egg and milk allergies often worsen eczema for children, although other food allergies are also common. Allergy testing is an important part of the evaluation of patients with atopic dermatitis, and avoidance of these triggers, both environmental and food allergens, can significantly improve the disease.

Sources

  • Piliang M. Atopic Dermatitis. Cleveland Clinic. 
  • Weston WL. Howe W. Pathogenesis, clinical manifestations, and diagnosis of atopic dermatitis (eczema). In: UpToDate. Corona, R (Ed). UpToDate.

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