Diagnosis of atopic dermatitis: From bedside to laboratory

Atopic dermatitis (AD) is essentially diagnosed clinically. In babies and young children, the diagnosis is usually straightforward. Dry, very pruritic dermatitis starts on the cheeks, with the neck and trunk often involved, but the nappy area spared. Limb involvement follows later – first extensoral, later classically flexural. This is mostly the picture of AD. In adults, the presentation may vary widely. Classic flexural dermatitis may persist, but erythroderma (whole-body involvement), head and neck dermatitis, isolated hand dermatitis and nummular dermatitis may be more difficult to identify as AD.