Signs and Symptoms of Atopic Dermatitis
Approximately 50% of those who develop the condition display symptoms before the age of 1, and 80% display symptoms within the first 5 years of life. Atopic skin often is dry and sensitive, and intense itching is a cardinal feature. The constant rubbing and scratching this provokes sets in motion an itch-scratch cycle that is difficult to control. People with this condition have a low threshold for itch, and mild irritants such as wool clothing and most soaps can worsen the symptoms.
Newly affected areas are quite itchy, and the skin is red with weeping or blistering. Scratching can create wounds, and the skin can become thick and dark, with marked folds, over time. In chronic atopic dermatitis, thick, scaly bumps develop where the skin has been rubbed and scratched.
The distribution of atopic dermatitis varies with age:
- Infants present with red, scaly, oozy, crusty cheeks, and the neck, arms, and legs are involved. Symptoms clear in about half of these children by the time they are 2 or 3 years old.
- In older children, the folds on the arms and behind the knees can become dry, thick, scaly, and very itchy. Atopic dermatitis typically becomes less severe as the child matures.
- In young adults, symptoms typically appear on the face, neck, hands, feet, fingers, and toes. Most of the lesions are thickened, leathery, and dull-looking.
Seventy-five percent of the cases greatly improve by the time children reach adolescence, but 25% continue to have difficulties with the condition through adulthood.
Eyelid dermatitis is commonly associated with atopic dermatitis, and the intense itching and vigorous rubbing this provokes can cause deformities on the corneas of the eyes. Because atopic skin is often scaly and cracked, it is susceptible to secondary bacterial and viral infections. The herpes simplex virus can spread over the skin, causing eczema herpeticum, a condition characterized by itchy vesicles (similar in appearance to chickenpox) and large areas of raw or crusted skin. Infection with Staphylococcus bacteria (staph infection) can cause inflammation, irritation, oozing, and crusting.
Various environmental factors (e.g., dust mites, weeds, animal dander, molds) can cause the condition to flare. Foods, too, can make the skin rashes in atopic dermatitis worse, but this seems to happen only in a small number of people. Eggs, milk, peanuts, soy, nuts, fish, and wheat are the foods most commonly associated with worsening symptoms.
Atopic Dermatitis Diagnosis
Diagnosis of atopic dermatitis is based on a positive family history, dry skin, prominent hair follicles, and itchy, red, crusted atopic areas. Psoriasis, scabies (infestation with a skin mite), and other types of eczema, such as contact dermatitis, should be ruled out. Early diagnosis allows effective treatment and rapid resolution.