What Causes Eczema – Allergies Advice from About.com

This person has atopic dermatitis on the arms. Red, scaly plaques can be seen on the inside of the elbows. In adults, atopic dermatitis usually involves the body creases, or flexural areas. adam.about.net

By Daniel More, MD

Updated December 29, 2014.

It is important to note that atopic dermatitis is not a rash that itches. Rather, it is an itch, that when scratched, results in a rash. Therefore, if the itching can be controlled, and there is no scratching, there will be no rash (eczema).

Atopic dermatitis is very common in childhood, affecting up to 20% of kids, usually before the age of 5. The disease is less common in adults, affecting only 1 to 3% of the population, although can start at any age.

It is rare to see atopic dermatitis in adults over 50 years of age.

In general, when atopic dermatitis occurs in infants, it usually is more severe, although many cases resolve or improve in later childhood.

Children with atopic dermatitis are much more likely to have other allergic diseases, including allergic rhinitis and asthma.

There are three criteria that must be present in order to diagnose atopic dermatitis:

In older children and adults, the location of the rash changes to classically involve the skin in front of the elbows and behind the knees.

Eczema can also involve the face (especially the eyelids), and may be limited to the palms of the hands and soles of the feet in certain people.

People with atopic dermatitis are more susceptible to skin infections by various bacterial, fungal and viral infections. Many are have large amounts of a common skin bacterium, called 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 cause severe skin infections in people with atopic dermatitis.

Allergies can be a significant trigger for itching in people with atopic dermatitis. Usually 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.

Food allergies can also be a major trigger for people with atopic dermatitis, particularly in children. Egg and milk allergy are the most common food allergies in children worsening eczema, 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.

Find out more about the prevention and treatment of atopic dermatitis.

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DISCLAIMER: The information contained in this site is for educational purposes only, and should not be used as a substitute for personal care by a licensed physician. Please see your physician for diagnosis and treatment of any concerning symptoms or medical condition.

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What Causes Eczema - Allergies Advice from About.com