Atopic dermatitis is a chronic skin condition resulting in persistent itching with inflammation of the outer lying layers of the skin. It is common in those with an allergic constitution and is often seen in conjunction with conditions like hay fever (allergic rhinitis) and asthma. Atopic dermatitis is commonly known as eczema, particularly infantile eczema when it occurs in children. However eczema describes a wide range of inflammatory conditions and is synonymous with the term dermatitis.
Why does atopic dermatitis occur?
Causes of Atopic Dermatitis
The exact cause for atopic dermatitis in unknown although person’s with a personal or family history of allergic conditions are more likely to develop atopic dermatitis. Atopic dermatitis is usually triggered and aggravated by inhaled or ingested (foods and drinks) allergens.
Skin inflammation results from an immune mediated hypersensitivity, meaning that allergens trigger the immune system. The immune cells (white blood cells) and chemical mediators of inflammation then cause skin inflammation at the affected area of the skin. This increased immune activity can be measured and monitored by the immunoglobulin-E (IgE) levels in the blood. In cases of atopic dermatitis, ingested and inhaled allergens usually aggravate the condition in children while inhaled allergens appear to the main aggravating factor in adults.
- Picture of Atopic Dermatitis
Immune mediated hypersensitivity is also the mechanism of action that causes other allergy related conditions like asthma and hay fever. These three conditions, asthma, hay fever and eczema, are known as the allergic triad. Sometimes one or more conditions can occur simultaneously or one condition may resolve and another appear.
Common inhaled and surface allergens include tree and grass pollen, excrement from house dust mite, cockroaches and molds. In terms of ingested allergens, many foods may aggravate atopic dermatitis but the five most allergenic foods are known to be milk and dairy products, egg yolk, wheat, soya and nuts. Other foods and food additives like preservatives, colorant or flavorants may also irritate the skin.
What does atopic dermatitis look like?
Signs and symptoms of Atopic Dermatitis
The most common signs and symptoms of atopic dermatitis is severe itching, with a red, dry rash and rough or cracked skin. With time, the skin may become darker especially if left untreated.
Atopic dermatitis may appear similar to other skin conditions like contact dermatitis and seborrheic dermatitis. It usually begins in infancy as a red, crusting rash and is frequently seen at the folds of the body, elbows, behind the knees, behind the ears and neck. In severe cases, atopic dermatitis may appear to be weeping either due to oozing plasma or pus when infected by bacteria and fungi. In these cases, it is commonly known as ‘wet eczema’.
In infants, atopic dermatitis can affect large areas of the skin or occur at multiple sites. In older children and adults, atopic dermatitis usually affects one or two areas and is not widespread. Atopic dermatitis usually improves after 3 to 4 years of age but acute episodes may recur throughout life.
- Infantile Eczema Picture from Health.com
While the condition is caused by an immune mediated hypersensitivity, the rash is easily irritated by sun, certain chemicals, creams, soaps and clothing. It may also worsen during certain seasons or at certain ranges of temperature.
How to treat and manage atopic dermatitis?
Treatment & Management of Eczema
In infants and children, eczema should be managed conservatively as far as possible. Simple lifestyle measures can greatly improve the condition. Some of the common changes advocated by most health care professionals is to discontinue using strongly scented creams and soaps. In fact, soap should be avoided altogether in children and rather a non-scented aqeous cream should be used in place of soap when bathing.
Lipid based creams, rather than water based creams, should be used as emollients to coat the skin and form an artificial barrier to protect the skin from the environment. This prevents further drying of the skin. Most atopic dermatitis sufferers react to house dust mite which is abundant in couches and bed mattresses. Cleaning will only offer limited relief and water proof plastic coverings should be used to reduce exposure to house dust mite. Exposure to pets, especially dogs and cats, should be limited as far as possible.
To reduce the chance of a secondary bacterial infection, the finger nails should be kept short to reduce damage to the skin when scratching. Thick applications of petroleum jelly may be useful, especially at night, to lubricate the skin and limit the damage caused by scratching.
Corticosteroid creams are often used to treat atopic dermatitis but it should be used cautiously in children. If a corticosteroid cream is used, it should not be continued for more than 6 weeks although in severe cases, it may be utilized for up to 3 months. Antihistamines may be helpful in reducing itching. In case of infection, antibiotics or an antifungals may be necessary.
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