Atopic dermatitis, which often develops within the first few months of life, is a disease of unknown etiology. However, in many cases T-cell function is defective and serum IgE concentrations are elevated, which suggest that the immunological system is involved. Blockade of cutaneous β-adrenoreceptors has also been described. Other members of the immediate family are commonly affected, and relatives may have or may develop allergic rhinitis or asthma. The condition usually resolves spontaneously between the age of 5 and 8 years but it may persist into adulthood. Exacerbations may occur during periods of physical or emotional stress.

Weeping eczematous papules that are intensely pruritic develop in the face in infants, particularly on the cheeks. These lesions often extend to other skin surfaces later in childhood, including the scalp, wrists, flexor folds of the elbows and knees, and buttocks. Scratching leads to the formation of excoriations and infiltrated areas which subsequently become thickened or lichenified. Later, the lesions become drier, more scattered, and typically localized in the flexor folds of the neck, elbows, wrists and knees. Pustules and crusts are signs of secondary infection. Periorbital erythema and oedema are common.

Prevention and management

It is particularly important to explain to parents the chronic, relapsing nature of the disease and the factors that influence its course. Soaps, particularly those containing irritants or perfumes, should be avoided when washing children. Contact with detergents, domestic animals and clothes made from wool should also be avoided. Pruritus may be partially relieved by applying wet dressings to exudative lesions and emollients to lichenified plaques. If topical hydrocortisone, 1% concentration, is ineffective, the use of betamethasone valerate, other corticosteroids of comparable potency, or more potent corticosteroids such as oral prednisolone should be undertaken with care and with time-limitations to avoid side-effects. Topical antihistamines are not effective and should be avoided because of the risk of sensitization. However, oral antihistamines, particularly hydroxyzine, can be given at night to relieve pruritus and to facilitate sleep. Non-sedating antihistamines can be given during the day, and may provide some symptomatic relief. Since secondary staphylococcal infections, which can be subclinical or clinical, are common and can cause exacerbations, an oral antibiotic such as erythromycin can be given for 7-10 days (see Erythromycin - Dosage and administration), or a topical antibiotic such as mupirocin ointment can be applied to the skin.