TAILIEUCHUNG - Chapter 053. Eczema and Dermatitis (Part 3)

Lichen Simplex Chronicus Lichen simplex chronicus may represent the end stage of a variety of pruritic and eczematous disorders, including atopic dermatitis. It consists of a circumscribed plaque or plaques of lichenified skin (thickening of the skin and accentuation of normal skin markings) due to chronic scratching or rubbing. Common areas involved include the posterior nuchal region, dorsum of the feet, and ankles. Treatment of lichen simplex chronicus centers on breaking the cycle of chronic itching and scratching. High-potency topical glucocorticoids are helpful in most cases, but in recalcitrant cases, application of topical glucocorticoids under occlusion, or intralesional injection. | Chapter 053. Eczema and Dermatitis Part 3 Lichen Simplex Chronicus Lichen simplex chronicus may represent the end stage of a variety of pruritic and eczematous disorders including atopic dermatitis. It consists of a circumscribed plaque or plaques of lichenified skin thickening of the skin and accentuation of normal skin markings due to chronic scratching or rubbing. Common areas involved include the posterior nuchal region dorsum of the feet and ankles. Treatment of lichen simplex chronicus centers on breaking the cycle of chronic itching and scratching. High-potency topical glucocorticoids are helpful in most cases but in recalcitrant cases application of topical glucocorticoids under occlusion or intralesional injection of glucocorticoids may be required. Oral antihistamines such as hydroxyzine 10-25 mg every 6 h or tricyclic antidepressants with antihistaminic activity such as doxepin 10-25 mg at bedtime are useful primarily due to their sedating action. Higher doses of these agents may be required but sedation can become bothersome. Patients need to be counseled regarding driving or operating heavy equipment after taking these medications. Contact Dermatitis Contact dermatitis is an inflammatory process in skin caused by an exogenous agent or agents that directly or indirectly injure the skin. This injury may be caused by an inherent characteristic of a compound irritant contact dermatitis ICD . An example of ICD would be dermatitis induced by a concentrated acid or base. Agents that cause allergic contact dermatitis ACD induce an antigen-specific immune response poison ivy dermatitis . The clinical lesions of contact dermatitis may be acute wet and edematous or chronic dry thickened and scaly depending on the persistence of the insult see Fig. 52-10 . Irritant Contact Dermatitis ICD is generally well demarcated and often localized to areas of thin skin eyelids intertriginous areas or to areas where the irritant was occluded. Lesions may range from minimal .

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