Eczema Rashes: Causes and Treatments

Atopic dermatitis (AD) is a chronic, highly itchy skin condition that frequently relapses. It most often begins in childhood, although a small number of people develop the disease as an adult. One of the most noticeable symptoms of AD is the rash, a type of lesion that may involve patches of dry, scaly skin.¹

What are eczema lesions?

Acute lesions of atopic dermatitis are red, have papules (bumps or pimples without pus), leak fluid (weepy) and have scratch marks, breaks in the skin, or appear as the skin has been rubbed raw. Chronic lesions of AD have areas of thickened scaly skin (also called lichenification) and scarred, lumpy skin (also called fibrotic nodules). Chronic lesions and acute lesions may occur in the same areas of skin.¹

Where do rashes occur?

The rash caused by atopic dermatitis usually appears in a characteristic pattern depending on the age of the person:

• In infants and young children, the rash shows up on the scalp or face, especially the cheeks or chin, and the arms and legs, particularly the outer creases of the elbows and knees in infants and the inner creases of the joints in young children
• In older children, AD frequently appears as a rash on the inside creases of the elbows or knees, the neck, wrists, ankles, and/or the crease between the buttocks and the thighs
• In adults, the rash can appear anywhere, including the inner creases of the elbows or knees, and/or the nape of the neck, or it may be localized to just the hands, feet, or nipples²

What causes eczema rashes?

Atopic dermatitis is caused by a combination of genetic, immunologic, and environmental factors.

Filaggrin and eczema lesions

In people with AD, there can sometimes be a decrease or lack of filaggrin in the skin. Filaggrin is a protein that plays a key role in the structure and formation of the outermost corneal layer of the skin. The lack of or decrease in filaggrin has been traced back to genetic mutations in the FLG gene. Not having enough filaggrin in the skin layers leads to a reduced ability to maintain the skin’s natural amount of water. Excess water loss can lead to dry skin, which then causes itchiness. The lack of filaggrin may also allow for the entry of airborne allergens to enter the skin, which could lead to an inflammatory response by the immune system.

Damaged skin barrier and eczema lesions

Another theory suggests that the normal pH of the skin barrier may be affected by filaggrin defects, which could lead to the overgrowth of bacteria. This could then trigger the immune system to create inflammatory skin lesions.

Immune system dysfunction and eczema lesions

There is also emerging evidence that the dysfunction in the immune system in patients with eczema not only causes disease but also decreases the amount of functional filaggrin. Immune system dysfunction also creates an increase in inflammation in people with AD.^3,4

How to treat rashes

Moisturizers are one of the basic necessities for people with AD, regardless of the severity of their disease. Some of the anti-inflammatory medications available for treating AD also come in moisturizer formulations, which can help provide additional barrier repair and control itchiness.

Medications for eczema

Medications used in the treatment of AD include:

• Topical corticosteroids, to reduce redness, inflammation, and itching
• Topical calcineurin inhibitors, to stop the dysfunctional immune response and reduce redness and itching
• Immunosuppressants, which also target the dysfunctional immune response to reduce symptoms
• Antibiotics, to fight infection⁵