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Some patients’ disease may persist through adulthood. In others, a tendency for dry

               and irritable skin that easily develops eczematous changes may persist after AD
               resolves. A propensity for recurrent hand dermatitis may remain in adults who had AD in

               their childhood. Many children later on develop allergic rhinitis or bronchial asthma.


               3.10.2. Seborrheic Dermatitis



               Seborrheic dermatitis is a papulosquamous disorder patterned on the sebum-rich
               areas of the scalp, the face, and the trunk.  In addition to sebum, this dermatitis is

               linked to  Pityrosporum ovale, immunologic abnormalities, and activation of
               complement. It is commonly aggravated  by changes in humidity, trauma (eg,

               scratching), seasonal changes, and  emotional stress. The severity varies from mild
               dandruff to exfoliative erythroderma. Seborrheic dermatitis may worsen in Parkinson

               disease and in AIDS.


               Seborrheic dermatitis is associated with normal levels of  P ovale but an abnormal

               immune response.
               The incidence of seborrheic dermatitis is  3-5%, with a worldwide distribution. In

               infants, it occurs as cradle cap or commonly as a flexural eruption or rarely as

               erythroderma.

               Clinical presentation


               Skin lesions present as greasy scale over  red, inflamed skin. Infectious eczematoid

               dermatitis, with oozing and crusting, suggests secondary infection. A seborrheic
               blepharitis may occur independently.



               Distribution follows the oily and hair-bearing areas of the head and the neck, such as

               the scalp, the forehead, the eyebrows, the lash line, the nasolabial folds, the beard,
               and the postauricular skin. Presternal or interscapular involvement is more common

               than the nonscaling intertrigo of the umbilicus, axillae, inframammary and inguinal
               folds, perineum, or anogenital crease that may also be present.








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