Scaly dermatoses: What’s that itch?

Abstract

Chronic scaly dermatoses include dandruff, seborrheic dermatitis, and psoriasis. These disorders involve the epidermis, the uppermost layer of skin. The primary manifestation is scaling of the skin, with inflammation, erythema, and other changes in appearance of variable degree and severity. Individuals with scaly dermatoses can receive significant relief through focused OTC products and important educational tips from their pharmacist. Dandruff is the less-inflammatory form of scaly dermatoses. It manifests as a more subtle dermatitis with relatively fine scaling confined to the scalp and occasionally includes mild erythema or inflammation. The goals of self-treatment for dandruff are 1) to reduce the epidermal turnover rate of the scalp skin by reducing the number of Malassezia fungi on the scalp, 2) to minimize the cosmetic embarrassment of visible scaling, and 3) to minimize itch. Shampooing with a general-purpose nonmedicated shampoo daily or every other day often is sufficient to control mild to moderate dandruff. Nonprescription medicated antidandruff shampoos, including those with either a cytostatic agent or ketoconazole, are other options. Topical cytostatic agents include pyrithione zinc, selenium sulfide, and coal tar. These agents can decrease the rate of epidermal cell replication and are of limited effectiveness. Contact time is the key to any efficacy, so medicated shampoos should be massaged into the scalp and left on the hair for three to five minutes before rinsing. Use the medicated shampoo daily for one week, then two to three times weekly for two to three weeks, and thereafter once weekly or every other week to control the disorder. Nonprescription ketoconazole antifungal shampoo is active against most pathogenic fungi but is indicated specifically for Malassezia infections. This product is used twice a week for 4 weeks, with at least three days between each treatment. Once the disorder is controlled, apply once weekly to prevent relapse. Seborrheic dermatitis affects the scalp, face, and chest (usually the sternum) and typically features significant inflammation and erythema. The goals of self-treatment for seborrheic dermatitis are 1) to reduce inflammation and the epidermal turnover rate of the scalp skin by reducing the level of Malassezia fungi, 2) to minimize or eliminate visible erythema and scaling, and 3) to minimize itch. Because of the inflammatory nature of seborrheic dermatitis, treatment is similar to, but more aggressive than, that for dandruff. Topical corticosteroids are needed more frequently to treat the more significant inflammation in seborrheic dermatitis. Corticosteroid products may be used to manage seborrheic dermatitis whenever erythema persists after therapy with medicated shampoos. Hydrocortisone ointment should be applied no more than twice daily because of the reservoir effect of the stratum corneum, which slowly releases the corticosteroid over time, and potential greasiness. Treatment should continue until symptoms subside but for no more than 7 consecutive days since seborrheic dermatitis is rarely cured by nonprescription treatment. If the disorder worsens or symptoms persist longer than 7 days, a dermatologist or other knowledgeable health care provider should be consulted. Psoriasis is a highly inflammatory skin disorder characterized by raised plaques and adherent thick, silvery white scales. The goals of self-treatment for psoriasis are 1) to control or eliminate the signs and symptoms (i.e., inflammation, scaling, itching) and 2) to prevent or minimize the likelihood of flares. Mild cases of psoriasis, characterized by the presence of a few localized lesions no larger than a quarter, are amenable to self-treatment with topical agents. Patients with psoriasis should be encouraged to bathe with lubricating bath products two to three times per week using tepid water. Daily lubrication of the skin after a bath or shower is essential. Emollients moisturize, lubricate, and soothe dry and flaky skin as well as reduce fissure formation within plaques and help maintain flexibility of the surrounding skin. Emollients should be applied to the lesions within minutes of bathing. To be effective, these products need to be applied liberally with gentle rubbing, up to 4 times daily. Hydrocortisone ointment 1% is the nonprescription medication of choice for treatment of bright red lesions. In some patients, nonprescription treatment may be ineffective and more aggressive treatments may be needed. Psoriasis can be controlled but not cured, and remissions do occur. Patients should be educated on controlling the disorder to help prevent flare-ups and to better understand this disorder to help reduce associated emotional stress and frequency of psychogenic exacerbations.