Introduction to Atopic Dermatitis

Atopic dermatitis is characterized by superficial skin inflammation and intense itching. Although atopic dermatitis may appear at any age, it typically begins during infancy or early childhood. It may then subside spontaneously, followed by exacerbations in late childhood, adolescence, or early adulthood. Atopic dermatitis affects less than 1% of the population.

Causes
Atopic dermatitis is a chronic, inherited skin disorder in which the immune system produces a hypersensitivity reaction to environmental allergens that are often difficult to identify.

Exacerbating factors of atopic dermatitis include irritants, infections (commonly caused by Staphylococcus aureus), and some allergens. Although no reliable link exists between atopic dermatitis and exposure to inhalant allergens (such as house dust and animal dander), exposure to food allergens (such as soybeans, fish, or nuts) may coincide with flare-ups of atopic dermatitis.

Signs and symptoms
Scratching the skin causes vasoconstriction and intensifies pruritus, resulting in erythematous and weeping lesions. Eventually, the lesions become scaly and lichenous. Usually, they’re located in areas of flexion and extension, such as the neck, antecubital fossa, popliteal folds, and the backs of the ears. Patients with atopic dermatitis are prone to unusually severe viral infections, bacterial and fungal skin infections, ocular complications, and allergic contact dermatitis.

Diagnosis
Typically, the patient has a history of atopy, such as allergic rhinitis asthma, or urticaria; family members may have a similar history. Laboratory tests reveal eosinophilia and elevated serum immunoglobulin E levels.

Treatment
Measures to ease this chronic disorder include meticulous skin care, environmental control of offending allergens, and drug therapy.

Drug therapy includes a corticosteroid and an antipruritic. 

Active dermatitis responds well to a topical corticosteroid, such as fluocinolone acetonide and flurandrenolide; however, the drug should be applied immediately after bathing for optimal penetration. 

An oral antihistamine, especially a phenothiazine derivative such as methdilazine and trimeprazine, can help control itching. A bedtime dose of an antihistamine may reduce involuntary scratching during sleep. If a secondary infection develops, an antibiotic is necessary.

Special considerations

• Monitor the patient’s compliance with drug therapy, and discuss adverse effects of corticosteroid therapy as appropriate.
• Teach the patient when and how to apply a topical corticosteroid.
• Tell the patient to bathe in tepid water (96° F [35.6° C]), and emphasize the importance of good personal hygiene and keeping nails short to limit further irritation and infection.
• Be alert for signs and symptoms of secondary infection; teach the patient how to recognize them as well.
• If the patient’s diet has been modified to exclude food allergens, monitor his nutritional status.
• Discourage the use of laundry and bath additives.
• Offer support to help the patient and his family cope with this chronic disorder.
• Because this disorder may frustrate the patient and strain family ties, stress reduction and counseling may play a role in treatment.