Xerosis

Dryness of the skin.

Dry skin is common in the elderly. The cause is unknown but appears to be related to altered lipid composition of the stratum corneum and to other subtle changes in epidermal differentiation. The HMG-CoA reductase inhibitors (statins) may also produce acquired ichthyosis and severe xerosis.

Symptoms and Signs

Dry skin tends to be itchy and scaly, especially over the lower legs, forearms, and hands. Symptoms are often worse in the winter because of lower humidity both indoors (due to central heating) and outdoors (due to exposure to cold and wind). A complication of xerosis called eczema craquelé, or asteatotic eczema, develops when the stratum corneum (the outermost barrier layer) is compromised by fissures or excoriations, allowing environmental irritants to penetrate the skin and causing inflammation.

Prophylaxis and Treatment

Patients should bathe only once a day and avoid using strong soaps, rubbing alcohol, detergents, and other drying agents whenever possible. Patients should also avoid placing potentially irritating materials (eg, wool) next to the skin.

Emollients are helpful if applied frequently and liberally, especially after bathing, when the skin is still moist. Over-the-counter (OTC) emollients differ in cost and quality, but there is no obligate relationship between the two. White petrolatum is an inexpensive and effective emollient. Scented emollients are best avoided because they may irritate dry skin and cause contact sensitization.

Prescription creams and lotions containing urea or an -hydroxy acid (eg, lactic acid) help remove scales, keep the skin hydrated, and prevent symptoms. A low-potency topical corticosteroid ointment, such as 1 or 2.5% hydrocortisone, is useful in treating inflamed dry skin (see Table 123-5). It should be applied to affected areas after bathing and at bedtime. Prolonged use is discouraged because of systemic absorption. A humidifier can help increase humidity during the winter.