Atopic Dermatitis

Atopic dermatitis (AD) is a pruritic disease of unknown origin that usually starts in early infancy (an adult-onset variant is recognized); it is characterized by pruritus, eczematous lesions, xerosis (dry skin), and lichenification (thickening of the skin and an increase in skin markings).

AD may be associated with other atopic (immunoglobulin E [IgE]–associated) diseases (eg, acute allergic reaction to foods, asthma, urticaria, and allergic rhinitis).

Sex

·         The male-to-female ratio for atopic dermatitis is 1:1.4.

Age

·         In 85% of cases, atopic dermatitis occurs in the first year of life; in 95% of cases, it occurs before age 5 years. The incidence of atopic dermatitis is highest in early infancy and childhood. 

·         History

·         Incessant pruritus is the only symptom of atopic dermatitis (AD); children often scratch themselves uncontrollably. Although pruritus may be present in the first few weeks of life, parents become more aware of the itch as the itch-scratch cycle matures when the patient is aged approximately 3 months. The disease typically has an intermittent course with flares and remissions occurring, often for unexplained reasons.

Laboratory Studies

·         No chemical marker for the diagnosis of atopic dermatitis is known.

·         Laboratory testing is seldom necessary

Medical Care

Patients with atopic dermatitis do not usually require emergency therapy, but they may visit the emergency department for treatment of acute flares caused by eczema herpeticum and bacterial infections. For further information on treatment, see the NICE Guidelines Issued for Treating Atopic Eczema in Children.^[34]

·         Moisturization in atopic dermatitis

o    Depending on the climate, patients usually benefit from 5-minute, lukewarm baths followed by the application of a moisturizer such as white petrolatum. Frequent baths with the addition of emulsifying oils (1 capful added to lukewarm bath water) for 5-10 minutes hydrate the skin. The oil keeps the water on the skin and prevents evaporation to the outside environment. In infants, 3 times a day is not a great burden; in adults, once or twice a day is usually all that can be achieved. Leave the body wet after bathing.

o    Advise patients to apply an emollient such as petrolatum or Aquaphor all over the body while wet, to seal in moisture and allow water to be absorbed through the stratum corneum. The ointment spreads well on wet skin. The active ingredient should be applied before the emollient. Newer emollients such as Atopiclair and Mimyx have been advocated as having superior results, but they are expensive and need further evaluation.

·         Topical steroids in atopic dermatitis

o    Topical steroids are currently the mainstay of treatment. In association with moisturization, responses have been excellent.

o    Ointment bases are preferred, particularly in dry environments.

o    Initial therapy consists of hydrocortisone 1% powder in an ointment base applied 2 times daily to lesions on the face and in the folds.

o    A midstrength steroid ointment (triamcinolone or betamethasone valerate) is applied 2 times daily to lesions on the trunk until the eczematous lesions clear.

o    Steroids are discontinued when lesions disappear and are resumed when new patches arise.

o    Flares may be associated with seasonal changes, stress, activity, staphylococcal infection, or contact allergy.

o    Contact allergy is rare but accounts for increasing numbers of flares. These are seen mostly with hydrocortisone.

·         Diet

·         Avoid foods that provoke acute allergic reactions (hives, anaphylaxis). Most frequently, allergic reactions occur to peanuts (peanut butter), eggs, seafood, milk, soya, and chocolate. Additionally, advise patients to apply a barrier of petroleum jelly around the mouth prior to eating to prevent irritation from tomatoes, oranges, and other irritating foods.

·         Activity

Advise patients to avoid activities that cause excessive sweating. Also, swimming in an outdoor pool (or wading pool for babies) in summer provides therapeutic benefit by exposing the person

to the sun but avoiding the heat.

Anti-inflammatory agents

Mild topical corticosteroid mixed in petrolatum. Has mineralocorticoid and glucocorticoid effects and anti-inflammatory activity.

Use 1% ointment 2-3 times daily.

Antihistamines are also used  for itching