A nine-year-old girl presents with a three-month history of severe persistent itching and skin lesions throughout most of her body. Physical examination revealed numerous 15 to 20 mm papulonodular lesions over all the extremities and trunk with some confluence (see accompanying figure). Crusting and lichenification also were observed. No lesions were present on the face.
The answer is C: severe atopic dermatitis. Atopic dermatitis is a form of endogenous dermatitis resulting in pruritic inflammation of the epidermis and dermis, which commonly occurs in infants and children but can be found in adults. Atopic dermatitis affects more than 10 percent of children, and the majority of patients are affected during the first five years of life.1
Psoriasis is an inflammatory epidermal proliferative disorder of the skin, which is usually not intensely pruritic. The most common lesions are papules and nodules like those shown in the photograph, but in psoriasis they are sharply demarcated and covered by silvery white scale. The lesions most commonly involve areas of the body that experience repeated minor trauma, such as elbows, knees, scalp, feet, and hands. Associated findings may include fingernail pitting or thickening (50 percent of cases) and arthritis (up to 10 percent of cases).
Pemphigus vulgaris is an autoimmune bullous disease of the skin that usually occurs in adults and is rare in children. There is no pruritus. The lesions are flaccid vesicles or bullae that are initially localized in oral mucosa and later spread randomly to other parts of the body. This can be a serious and potentially fatal disorder.
Lichen planus is characterized by flat-topped, polygonal, violaceous papules, which are much smaller than the confluent papulo-nodular lesions seen in severe atopic dermatitis. The pruritus is variable. Lichen planus is uncommon in children. The common sites include wrists, shins, mucous membrane, lumbar area, and genitalia.
Sweet's syndrome is an uncommon disorder of the skin that generally has associated systemic symptoms like fever, arthralgias, and peripheral leukocytosis. The lesions are red-brown plaques and nodules over the head, neck, and upper extremities, which are painful rather than pruritic. Truncal lesions are uncommon, and approximately 10 percent of patients have an associated underlying malignancy.
Atopic dermatitis is frequently accompanied by a personal or family history of asthma, allergic rhinitis, or allergic skin involvement. The onset of the skin lesions is usually subacute or chronic. In infants, the extensor surface of the extremities, face, and trunk are involved, whereas children and adults have predilection for the flexural areas of the extremities, neck, and upper trunk. Patients with atopic dermatitis often have diffusely dry skin. Pruritic papules with vesicles are typical initially; these may become scaly and crusty later. Chronic lesions may have thickened lichenified skin with fibrotic papules and nodules as are seen in this case. The distribution of the lesions may become more diffuse in the chronic condition. Secondary infection is common, especially with Staphylococcus aureus.2
Atopic dermatitis may be confused with a number of the eczematous dermatitides including contact dermatitis, seborrheic dermatitis, and psoriasis. In dark-skinned patients, it is often difficult to differentiate the lesions from the other conditions as outlined above because of the lack of contrast between the lesions and uninvolved skin. In blacks, a subtype of atopic dermatitis occurs frequently where each papule involves a separate hair follicle, and is termed follicular eczema.
The diagnosis of atopic dermatitis is based primarily on clinical presentation and history. No laboratory tests are available to definitively establish a diagnosis of atopic dermatitis, although patients may have elevated levels of IgE and peripheral blood eosinophilia. The histopathologic changes seen in biopsy specimens of atopic dermatitis are nonspecific.
Common triggers of atopic dermatitis include dry skin, infection, physical or emotional stress, sweating, and skin irritants. These irritants can include soaps, detergents, cosmetics, wool and acrylic clothing, linens, and perfumes.
Symptomatic treatment consists of the use of moisturizers to prevent the itching caused by dry skin. Avoidance of any of the irritants or triggers is the cornerstone of therapy. Mild or no soap should be used when bathing. Hot baths or frequent bathing may cause drier skin and should be avoided. Oral antihistamines can help control itching. Use of H2 blockers in cases of severe pruritus may be helpful. Topical steroid ointments or creams in addition to cool wet dressings are useful in acute flares of the disease as well as in maintenance of healing in the chronic phase. Topical or oral antibiotics should be considered when there is suspicion of secondary infection, because this may be a cause of persistent pruritus.
In cases of severe intractable atopic dermatitis, systemic corticosteroids may be used. Other alternatives include phototherapy using ultraviolet radiation, cyclosporin, or recombinant IFN-g.3