Pharmacists are often asked about dry skin (xerosis, xeroderma), especially as the population ages. Dry skin affects perhaps 75% of those 64 and older. Patients ask for advice on preventing and treating dry skin and which products to use when excessive dryness has caused the skin to crack open and sometimes to bleed.
The skin is the largest organ, covering most of the body. It is a primary contact point for the external environment. It comes in contact with chemicals, soaps, clothing, extreme temperatures, and all ranges of moisture or dryness. It is a barrier that protects the body from the influx of various external chemicals and compounds and also prevents loss of fluids and electrolytes from the internal environment.
Manifestations of dry skin occur along a spectrum, becoming more serious as the condition persists and/or worsens. When the skin is overly dry, it initially reddens and develops cracks. The cracks appear like those seen in fine antique porcelain (eczema craquelé) and result from the loss of hydration in the epidermis. The cracks may occur along and accentuate the natural skin lines. The skin feels rough and uneven. If dryness continues, the skin also begins to scale or flake. As cracks extend and deepen, they form fissures. As the cracks and fissures enlarge, they eventually reach the depth of dermal capillaries. Erosion at this depth causes bleeding. Pruritus developing as a result of xerotic eczema is common with dry skin and may be severe.[7,8] Scratching to relieve it results in excoriation and possible infection of the skin. The pruritus can be differentiated from other pruritic conditions, such as contact dermatitis, by the absence of many of the common signs of dermatitis (e.g., vesicles, urticaria).
Dry skin is most common in the elderly. One study found that dry and pruritic skin was the most common problem in nursing homes. There are numerous reasons for this epidemiologic finding. Aging reduces activity in the sebaceous and sweat glands; decreases in sterol esters and triglycerides worsen the problem.[4,5] Generally, sebaceous activity peaks at puberty, remaining high until the age of menopause/climacteric.
There is a gender difference in sebaceous activity with aging. Male sebaceous activity remains robust until the eighth decade, while in women, levels start to fall much sooner. Women in their 60s have only 60% of the sebaceous activity they had in youth. The decline continues through much of the seventh decade.
Dry skin is also more common in patients with zinc or essential fatty acid deficiency, end-stage renal disease, hypothyroidism, neurologic disorders that decrease sweating, HIV, malignancies, or obstructive biliary disease, and in those who have had radiation.[1,4,10] Dry skin is one of the extraglandular manifestations of Sjögren's syndrome.[11,12] Atopicspeople who tend to develop atopic dermatitis, asthma, and hay feveralso frequently experience a great degree of xerosis.[13,14] Atopic dermatitis causes skin to become eczematic, pruritic, reddened, and scaly. Patients with diabetes often have autonomic neuropathy, a condition that increases the risk of xerosis.[15,16] Some medications, such as diuretics and antiandrogens, predispose a patient to dry skin. Topical medications that include alcohol also can dry the skin and should be avoided.
Winter is a peak time for dry skin due to the low humidity in ambient air and heating systems that force hot, dry air into the home or workplace. However, air conditioning also induces dry skin, since it removes much of the moisture from air.[2,4] Furthermore, artificial air treatment, frequently used in airplanes, also exposes the skin to dry air, desiccating its upper layers. Sunlight worsens dry skin by drying the epidermis. Tight clothing can increase the risk of dry skin and worsen existing dry skin through abrasive friction as the patient moves.
For many people, daily bathing is seen as an essential activity. It removes environmental filth, pollutants, and bacteria that cause unacceptable odors and skin infections. However, the surfactants and soaps used in bathing also decrease surface skin oils and adversely affect the skin's proteins. For this reason, some physicians advise older patients to bathe only on alternate days. Since harsh toweling causes unacceptable friction to the skin, patients should be taught to pat the skin dry gently. Further, a brief shower is better for the skin than a bath, since the cooler water temperature of the shower dries the skin less than sustained immersion in hot bathwater. Patients with xerosis should switch from highly irritating soaps and cleansers to milder soaps, and use bath oils cautiously. While some bath oils may leave a layer of protective oil on the skin, research has shown that they may also leave a residue of irritating chemicals, exacerbating the problem rather than alleviating it. Patients troubled by dry skin should minimize the amount of soap they use when showering. For instance, use of soap may be limited to the axillae, groin, and face during the majority of showers.
The most common site for dry skin is the legs (especially the anterolateral surfaces). The back, flanks, abdomen, waist, arms, and hands are also common sites. Washing the hands with soaps, detergents, and other lipid solvents several times a day removes natural skin oils and hastens desiccation. Some sites, such as the axillae, groin, face, and scalp, are less likely to have dry skin. The feet may be less prone to dryness, depending on the footwear chosen. After the morning bath or shower, feet are usually fully hydrated. Putting on shoes and socks shortly after bathing traps moisture in the feet, preventing dryness of the skin. Sandals or more open footwear do not protect against dryness.
Dry skin is more common when indoor and outdoor air have become progressively drier, perhaps as a result of low ambient temperature (e.g., wintertime in cold regions) combined with indoor heating systems. Therefore, the pharmacist should suggest replacement of humidity through the use of vapor therapy. Most pharmacies carry several types of humidification devices, including vaporizers and humidifiers. Vaporizers deliver heated steam to indoor air to increase humidity. While traditional vaporizers use electrodes immersed in a reservoir of water to produce steam, some use heating elements. Humidifiers use nonheating mechanisms to increase room humidity. Pharmacies generally stock three basic types of humidifiers. Some break water droplets into a mist and propel it into the room through the use of an impeller immersed in the reservoir. Others use a fan surrounding a wicking filter to evaporate water and increase humidity or an ultrasonic transducer to break water into an ultrafine mist. The humidification device should be run continually until the room reaches an indoor relative humidity of 50%. Inexpensive indoor humidity measuring devices are available at hardware and home supply stores. In addition to humidification, patients should maintain adequate internal hydration by drinking eight to ten 8-oz. glasses of water daily.
Patients with dry skin can choose from a host of products and interventions. The patient may presoak the area with warm water before applying emollients and/or moisturizers. Emollients close cracks and fissures by filling spaces around desquamating but attached skin flakes, sealing moisture into the skin through the production of an occlusive barrier.[4,15] The net effect is softening of the skin. Ingredients in emollients include mineral oils (e.g., liquid paraffin, petrolatum), waxes (e.g., lanolin, beeswax, carnauba), long-chain esters, fatty acids, and mono-, di-, and triglycerides.
Although the term moisturizer is often used interchangeably with emollient, moisturizers are products that combine a humectant with an emollient. Humectants hydrate the stratum corneum through a hygroscopic effect, increasing its elasticity. Humectant agents include alpha-hydroxy acids, such as lactic acid, glycolic acid, and tartaric acid, as well as urea, glycerin, and propylene glycol.
Most products actively marketed for dry skin employ a combination of ingredients to enhance efficacy in combating dry skin. Eucerin Dry Skin Therapy Plus Intensive Repair Lotion combines water, mineral oil, sodium lactate, urea, glycerin, wax, lanolin, alcohol, and other ingredients. Cetaphil Moisturizing Cream includes purified water, propylene glycol, petrolatum, glycerin, and lactic acid. Aveeno Moisturizing Bar for Dry Skin contains oat flour, water, glycerin, vegetable oil, and castor oil. Neutrogena Advanced Solutions Daily Moisturizer contains water, glycerin, and glycolic acid.
The pharmacist should be prepared to counter unreliable medical advice that the patient might attain on various Web sites. For instance, one Web site makes the sweeping and incorrect statement that dry skin is due to eczema, which in turn is a "disease of the whole metabolic system. The skin is trying to get rid of toxins in the bloodstream." It then recommends products containing sulfur and graphite. While sulfur can potentially cause folliculitis and/or systemic toxicity in large amounts, both ingredients are of unknown efficacy in the microdoses employed in homeopathy. These Web sites often lack references to allow legitimate exploration of their veracity.
US Pharmacist. 2005;30(3) © 2005 Jobson Publishing
Cite this: Managing Dry Skin - Medscape - Mar 21, 2005.