PRURITUS AND XEROSIS
Pruritus
(Itching)
Itching is a common complaint among the elderly. Patients with this complaint should be examined for inconspicuous primary skin lesions such as candidal dermatoses. Systemic disorders associated with generalized pruritus without primary skin lesions include liver and renal disease, iron deficiency anemia, lymphomas, leukemias, polycythemia vera, and parasitosis (usually of the GI tract). Some drugs (eg, barbiturates) can also cause itching. Disorders rarely associated with itching include diabetes mellitus, hyperthyroidism, and solid malignancies.
In research studies, an underlying disorder can be identified in up to 50% of patients with generalized pruritus. However, in most elderly patients, dry skin is more likely to cause pruritus than is an underlying condition.
Diagnosis and treatment: The elderly patient with pruritus who has no obvious skin disease should be examined for clinical clues to systemic disorders, such as lymphadenopathy, hepatosplenomegaly, jaundice, and anemia. Appropriate laboratory tests include a complete blood count; erythrocyte sedimentation rate; electrolyte, urea, and thyroid-stimulating hormone levels; and liver function tests. Urine should be tested for glucose, and if indicated by history or examination, stool should be tested for blood, ova, and parasites. When itching begins suddenly and is severe and unrelenting, an underlying disease should be strongly suspected, and laboratory evaluation should be thorough.
All patients complaining of pruritus should be treated for dry skin because even mild dryness can exacerbate itching, no matter what the cause. Patients should also be advised to avoid very hot baths or showers, as well as irritants such as harsh detergents and alcohol. Antihistamines and major tranquilizers are often prescribed, but they may pose dangers to the elderly and rarely produce a benefit that justifies the risk.
Xerosis
(Dry Skin)
Dry skin is a common cause of pruritus in the elderly. Symptoms are often worst in the winter, when central heating decreases humidity indoors and skin is exposed to cold and wind outdoors.
The skin is scaly, especially over the lower legs, forearms, and hands. The stratum corneum epidermidis may be compromised by fissures or excoriations, allowing environmental irritants to penetrate the skin and progressively worsen the condition, adding inflammation to dryness. This complication of xerosis is called erythema craquele or asteatotic eczema.
Treatment: Patients should be advised to keep the air in their home as humid as possible. They 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 (such as wool) next to the skin.
Emollients should be applied frequently and liberally, especially after bathing when the skin is still moist. Many lubricating agents are available, ranging from cosmetically elegant lotions to greasy ointments. White petrolatum (petroleum jelly) is an inexpensive and effective lubricant. Creams containing urea or lactic acid help remove scale, keep the skin hydrated, and prevent symptoms. Patients should avoid scented moisturizers because the perfume may irritate dry skin.
A low-potency topical corticosteroid ointment, such as 1% or 2.5% hydrocortisone, is useful in treating inflamed dry skin (see TABLE 101-3). It should be applied to affected areas after a bath or shower and at bedtime. Prolonged use should be discouraged because of systemic absorption.