Atopic Dermatitis: Natural History, Diagnosis, and Treatment

Atopic dermatitis is an inflammatory skin disease with early onset and with a lifetime prevalence of approximately 20%. The aetiology of atopic dermatitis is unknown, but the recent discovery of filaggrin mutations holds promise that the progression of atopic dermatitis to asthma in later childhood may be halted. Atopic dermatitis is not always easily manageable and every physician should be familiar with the fundamental aspects of treatment. This paper gives an overview of the natural history, clinical features, and treatment of atopic dermatitis. 1. Definition Atopic dermatitis is a common, chronic, relapsing, inflammatory skin disease that primarily affects young children. Atopy is defined as an inherited tendency to produce immunoglobulin E (IgE) antibodies in response to minute amounts of common environmental proteins such as pollen, house dust mites, and food allergens. Dermatitis derives from the Greek “derma,” which means skin, and “itis,” which means inflammation. Dermatitis and eczema are often used synonymously, although the term eczema is sometimes reserved for the acute manifestation of the disease (from Greek, ekzema, to boil over); here, no distinction is made. Over the years, many other names have been proposed for the disease, for instance, prurigo Besnier (Besnier’s itch), named after the French dermatologist Ernest Besnier (1831–1909). Allergic sensitization and elevated immunoglobulin E (IgE) are present in only about half of all patients with the disease, and therefore atopic dermatitis is not a definitive term. 2. Epidemiology Atopic dermatitis affects about one-fifth of all individuals during their lifetime, but the prevalence of the disease varies greatly throughout the world [1]. In several so-called industrialised countries, the prevalence increased substantially between 1950 and 2000 so much that many refer to as the “allergic epidemic.” However, current indications point to eczema symptoms having levelled off or even having decreased in some countries with a formerly very high prevalence, such as the United Kingdom and New Zealand. This indicates that the allergic disease epidemic is not increasing continually worldwide. Nevertheless, atopic dermatitis remains a serious health concern, and in many countries, particularly in the developing world, the disease is still very much on the rise. 2.1. Natural History Around 50% of all those with atopic dermatitis develop symptoms within their first year of life, and probably as many as 95% experience an onset below five years of age [2]. Around 75% with childhood onset of the disease