Atopic dermatitis is commonly known as eczema. The term eczema is non-specific and refers to the nature of the skin lesion and not a specific skin disorder. Here we will discuss atopic dermatis. This is a chronic dermatitis associated with a family or personal history of “atopic disease”, which includes asthma, allergic rhinitis, or atopic dermatitis. It is primarily a disease of childhood. It is thought to arise from a combination of genetic susceptibility and extrinsic factors. As with other eczemetous conditions, pruritus (itching) is a salient feature. The morphology of the rash as well as its distribution are dependent on age. Infantile atopic dermatitis exhibits the lesions of an acute dermatitis: papules and vesicles with oozing, weeping and crusting. It is located on the head, diaper area and extensor surfaces of the extremities. In children and adults the rash favors the flexor surfaces of extremities (i.e. the antecubital and popliteal fossae), as well as neck, face and upper chest. Chronic atopic dermatitis appears as lichenification (thickening of the skin with accentuated skin markings). Atopic individuals often have infraorbital creases called Dennie-Morgan lines.
With what can atopic dermatitis be confused?
Atopic dermatitis must be differentiated from other causes of dermatitis, as well as scabies. During infancy it is important to rule out the diseases Wiskott Aldrich syndrome (X-linked Recessive) and Hyper IgE Syndrome (Autosomal Dominant), which are both associated with cutaneous findings nearly identical to atopic dermatitis, but also have other associated signs and symptoms that would usually be noted.
How is atopic dermatitis diagnosed?
The diagnosis is made clinically based on the patient’s age and the typical appearance and distribution of lesions. Allergic respiratory disease (e.g. allergic asthma, seasonal allergies) is often present in patients or their family members. Biopsy is not necessary.
How is atopic dermatitis treated?
It is important to disrupt the itch/scratch cycle. Avoidance of environmental triggers, such as wool clothing, harsh soaps and detergents, known food allergies, and emotional and environmental triggers is important in this regard. Food allergies, especially to eggs, wheat, milk, and peanuts have been implicated in atopic dermatitis. Skin testing, followed by confirmatory challenge and elimination diets, may be beneficial but frequently is not. Moisturizers decease dry skin and reduce pruritus and are very helpful in breaking the itch/scratch cycle. Corticosteroids are the mainstay of medical treatment. Typical topical preparations, in order of increasing potency, are hydrocortisone 1%, triamcinolone 0.1%, and fluocinonide 0.05%. Widespread dermatitis is best treated with short term oral steroids (e.g. prednisone). Symptoms of widespread dermatitis can be treated with baths, with or without additives such as colloidal oatmeal (e.g. Aveeno) or tar (e.g. Cutar). Astringent dressings (e.g. Domeboro) are also beneficial. Pruritus can be relived with antihistamines such as hydroxyzine or diphenhydramine. Antibiotics (anti-Staph spectrum) are required in the event of secondary infection. Persons with atopic dermatitis often are heavily colonized with staph species. Flares often respond to antibiotics. Bleach baths (1 cap of bleach in a tub of water) can help reduce bacterial colonization. Topical tacrolimus and related medications, psoralen plus ultraviolet radiation (PUVA), or ultraviolet B radiation (UVB) are second-line therapies. The immune modulators, such as tacrolimus, especially useful on the face, since they do not have the skin thinning and neo-vascularizing side-effects of topical corticosteroids. If all else fails, systemic therapy with cyclosporine or azathioprine may help.
What is the prognosis for atopic dermatitis?
Atopic Dermatitis is marked by acute flares and periods of slow resolution. Most children outgrow the disease by adolescence, but many continue to have more circumscribed dermatitis. Secondary infection of the skin, due to breakdown of the epidermal barrier and decreased cellular immunity, is common.