Atopic dermatitis (or atopic eczema) is characterized by a family history of asthma, allergic rhinitis, eczema and it is cutaneous expression of the atopic state. The numbers of cases of atopic dermatitis or prevelance of atopic dermatitis are increasing all over the world.

What is the etiology of atopic dermatitis?

The etiology of atopic dermatitis is not well defined and there is certainly a strong genetic cause, because if both paretnts are affected by atopic dermatitis, the risk of children developing atopic dermatitis is more than 80%. When only one patrent is affected by atopic dermatitis the risk of children developing atopic dermatitis is approximately 50%.

What are the symptoms (clinical features) of atopic dermatitis?

The symptoms (and signs) of atopic dermatitis include:

· Itching and scratching with exacerbations and remissions of symptoms.

· The skin lesions are just like eczematous dermatitis.

· Strong family history of atopy such as asthma, allergic rhinitis, food allergies, eczema etc.

· Lichenification of skin.

· Symptoms lasts for more than 6 weeks before remissions of symptoms occur.

The symptoms of atopic dermatitis described above may vary according to age of the patient. At least 50% of atopic dermatitis patients manifest the disease withing first year of life and more than 80% manifest the disease by the age of 5 years. Approximately 80% of atopic dermatitis patients have asthma or allergic rhinitis. Itching and scratching is present in patients of atopic dermatitis of all age group, which is exacerbated by dry skin. Many of the cutaneous (skin) manifestations in atopic dermatitis patients, such as lichenification, are due secondary to rubbing and scratching.

In infants (below 1 year of age), atopic dermatitis manifests with characteristic weeping inflammatory patches and crusted plaques on the face, neck, and extensor surfaces of body.

In children and adolescents the symptoms of atopic dermatitis are generally dermatitis of flexural skin, especially in the antecubital (other side of elbow) fossa and popliteal fossa (other side of knee).

Atopic dermatitis may resolve spontaneously in many patients, but at least 50% of all individuals affected as children will have atopic dermatitis later in adult life. The distribution of skin lesions (dermatitis) may be same as seen during childhood, many adults have localized atopic dermatitis, which manifests as lichen simplex chronicus or hand eczema. In patients with localized disease, atopic dermatitis should be suspected if there is a typical personal history, family history, or there is presence of cutaneous stigmata of atopic dermatitis, such as perioral pallor, Dennie’s line (an extra fold of skin beneath the lower eyelid), increased palmar skin markings, and an increased incidence of skin infections with Staphylococcus aureus.

Treatment of atopic dermatitis:

General measures in treatment atopic dermatitis are important for symptomatic releif. Treatment of atopic dermatitis includes general measures such as avoidance of skin irritants, adequate moisturization of affected area of skin by application of emollients etc. The atopic dermatitis patients should be not bathe more than once daily using warm or cool water. Use only mild bath soaps. A topical anti-inflammatory agent in a cream or ointment base should be applied to skin lesions (dermatitis) immediately after bathing while the skin is still moist, and the remaining areas of skin should be lubricated using a moisturizer. Usually 30 grams of ointment (topical agent) is required to moisturize (cover) the entire body surface for an average adult. Topical anti-inflammatory agents should be used judiciously and treat secondary infections promptly and adequately, if it occurs.

Treatment of itching is required in atopic dermatitis as it is known as “an itch that rashes”. Antihistamines are preferred for reducing itching and scratching. Mild sedation of sedating antihistamines may be responsible for their antipruritic (anti-itching) action. The non-sedating second generation antihistamines or H2 blockers are not useful in controlling itching in atopic dermatitis. Sedating antihistamines can also help in sleeping better.

Low or mid potency topical glucocorticoids are used commonly for treatment of atopic dermatitis. Highly potent glucocorticoids are generally avoided due to high risk of skin atrophy and potential for systemic absorption and systemic side effects. On the face only low-potency topical glucocorticoids or non-glucocorticoid anti-inflammatory agents (such as tacrolimus ointment and pimecrolimus cream) are used to avoid skin atrophy. Tacrolimus and pimecrolimus are macrolide immunosuppressants and approved by the U.S. Food and Drug Administration (FDA) for topical use in atopic dermatitis.

There are also other broader effective agents available at present, which do not cause skin atrophy or do not suppress the HPA-axis (hypothalamic-pituitary-adrenal axis), but these agenta are more costly than topical glucocorticoids and potential for lymphomas therefore need caution while using these agents.

Secondary infection of eczematous skin may cause exacerbation of atopic dermatitis and need ptompt and adequate treatment. Crusted and weeping skin lesions are commonly infected with S. aureus. On suspicion of infection scrapings from the eczematous lesions should be cultured and patients treated with systemic antibiotics active against S. aureus and antibiotic changed if found to be different after antibiotic sensitivity test. A cephalosporin (e.g. cephalexin 250 mg 4 times a day for 7–10 days) or penicillinase-resistant penicillins (e.g. dicloxacillin) are preferred initially. More than 50% of S. aureus isolated are now methacillin resistant (MR) in many communities called community acquired MRSA (CA-MRSA). Currently trimethoprim/sulfamethoxazole (1–2 double strength 2 times a day), minocycline (100 mg 2 times a day), doxycycline (100 mg 2 times a day), or clindamycin (300–450 mg 4 times a day) etc. are preferred for treatment of secondary skin infection in atopic dermatitis with community acquired MRSA (CA-MRSA). The treatment is for 7-10 days.

Systemic glucocorticoids should be used only in severe exacerbations of atopic dermatitis, which do not respond to topical glucocorticoids. If systemic glucocorticoids are used to treat chronic atopic dermatitis, it will clear the skin for short duration and return invariably after stopping the treatment, sometime with worsening on the condition.