Atopic dermatitis

Atopic dermatitis (AD), also known as atopic eczema, is a type of inflammation of the skin (dermatitis). It results in itchy, red, swollen, and cracked skin. Clear fluid may come from the affected areas, which often thickens over time. While the condition may occur at any age, it typically starts in childhood with changing severity over the years. In children under one year of age much of the body may be affected. As children get older, the back of the knees and front of the elbows are the most common areas affected. In adults the hands and feet are the most commonly affected areas. Scratching worsens symptoms and affected people have an increased risk of skin infections. Many people with atopic dermatitis develop hay fever or asthma. Atopic dermatitis (AD), also known as atopic eczema, is a type of inflammation of the skin (dermatitis). It results in itchy, red, swollen, and cracked skin. Clear fluid may come from the affected areas, which often thickens over time. While the condition may occur at any age, it typically starts in childhood with changing severity over the years. In children under one year of age much of the body may be affected. As children get older, the back of the knees and front of the elbows are the most common areas affected. In adults the hands and feet are the most commonly affected areas. Scratching worsens symptoms and affected people have an increased risk of skin infections. Many people with atopic dermatitis develop hay fever or asthma. The cause is unknown but believed to involve genetics, immune system dysfunction, environmental exposures, and difficulties with the permeability of the skin. If one identical twin is affected, there is an 85% chance the other also has the condition. Those who live in cities and dry climates are more commonly affected. Exposure to certain chemicals or frequent hand washing makes symptoms worse. While emotional stress may make the symptoms worse, it is not a cause. The disorder is not contagious. The diagnosis is typically based on the signs and symptoms. Other diseases that must be excluded before making a diagnosis include contact dermatitis, psoriasis, and seborrheic dermatitis. Treatment involves avoiding things that make the condition worse, daily bathing with application of a moisturising cream afterwards, applying steroid creams when flares occur, and medications to help with itchiness. Things that commonly make it worse include wool clothing, soaps, perfumes, chlorine, dust, and cigarette smoke. Phototherapy may be useful in some people. Steroid pills or creams based on calcineurin inhibitors may occasionally be used if other measures are not effective. Antibiotics (either by mouth or topically) may be needed if a bacterial infection develops. Dietary changes are only needed if food allergies are suspected. Atopic dermatitis affects about 20% of people at some point in their lives. It is more common in younger children. Males and females are equally affected. Many people outgrow the condition. Atopic dermatitis is sometimes called eczema, a term that also refers to a larger group of skin conditions. Other names include 'infantile eczema', 'flexural eczema', 'prurigo Besnier', 'allergic eczema', and 'neurodermatitis'. People with AD often have dry and scaly skin that spans the entire body, except perhaps the diaper area, and intensely itchy red, splotchy, raised lesions to form in the bends of the arms or legs, face, and neck. AD commonly affects the eyelids where signs such as Dennie-Morgan infraorbital fold, infra-auricular fissure, and periorbital pigmentation can be seen. Post-inflammatory hyperpigmentation on the neck gives the classic 'dirty neck' appearance. Lichenification, excoriation and erosion or crusting on the trunk may indicate secondary infection. Flexural distribution with ill-defined edges with or without hyperlinearity on the wrist, finger knuckles, ankle, feet and hand are also commonly seen. The cause of AD is not known, although there is some evidence of genetic, environmental, and immunologic factors. Many people with AD have a family history of atopy. Atopy is an immediate-onset allergic reaction (type 1 hypersensitivity reaction) that manifests as asthma, food allergies, AD or hay fever. About 30% of people with atopic dermatitis have mutations in the gene for the production of filaggrin (FLG), which increase the risk for early onset of atopic dermatitis and developing asthma.