Dry skin is characterized by scaling and loss of suppleness and elasticity. The clinical appearance is one of fine scaling of the lower portions of the legs. In severe xerosis, loss of elasticity leads to cracking and fissuring, producing a superficial appearance of “cracked porcelain,” referred to as eczema craquelé (Fig. 183-1). Itching is a frequent concomitant and may lead to scratching and excoriation. Occasionally, dry skin is a consequence of hypovitaminosis A, drug reactions, hypothyroidism, or ichthyosis (vulgaris, acquired or other hereditary types).

One should teach the patient to avoid very strong soaps, detergents, and excessive contact with water, which dry the skin. Many soaps are essentially detergents and are extremely dehydrating. Substituting a well-oilated soap is recommended. Daily bathing may also be too drying, although a brief, cool shower is much less drying than a bath. Teaching the patient to avoid liquid shower soaps and gels (even if the label says they are “moisturizing”) can be helpful, as is adding a nonfragranced bath oil if baths are taken. Remind patients that if bath oil is used, they need to exercise caution regarding slips and falls. It is also wise to avoid exposure to mild irritants, such as solvents, and wool clothing. It is important to humidify the indoor environment, particularly during the winter months.

The treatment of preexisting dryness requires the addition of water and the application of hydrophobic agents. The physician should instruct patients to soak affected areas for several minutes and then apply a hydrophobic substance. Basically, most of the lotions and creams contain combinations of petrolatum (Vaseline), mineral oil, lanolin, glycerin, and water in proprietary blends. Ointments contain the lowest water content and are most effective. To make a cream, water and a preservative are blended in an ointment base. Lotions contain even more water and in fact can lead to further drying due to water evaporation. Plain petrolatum is inexpensive and effective, but it is not as pleasant to use as many proprietary preparations. Patients with an allergy to wool should avoid lanolin-based emollients (including Aquaphor).

A wide variety of agents are available, and patients are subjected to multimedia advertising for many of these products. Aveeno and Curel lotions are light and easily applied but are less occlusive than are emollient creams. Lac-Hydrin Five is a 5% ammonium lactate, and AmLactin is a 12% ammonium lactate that is available over the counter.

Creams containing ceramides are commercially available, both over the counter (CeraVe) and by prescription. Two creams have recently been approved by the U.S. Food and Drug Administration (FDA) as medical devices for treating atopic dermatitis that act to repair the barrier function. MimyX is a cream that is compounded with a bioactive fat—palmitoylethanolamide—which is considered lacking in atopic skin. Atopiclair is a moisturizer also for atopic dermatitis and contains glycyrrhetinic acid. Neither cream contains topical steroids or calcineurin inhibitors, and they are similar in their effectiveness to low-potency topical steroids.

Aquaphor and Elta are greasier than the aforementioned lotions and creams and are more effective in decreasing xerosis. Plain white petrolatum may be the most economical emollient.

The many expensive skin creams do little to retain moisture in the skin. Hygroscopic agents such as urea, α-hydroxy acids, sorbitol, and glycerol have chemical properties that retain moisture in the skin. Most moisturizers contain propylene glycol. If a patient experiences irritation with use of a facial moisturizer, it may be the propylene glycol that is causing the problem.

In severe cases, or to achieve more rapid results, topical corticosteroids may be applied. The use of Lac-Hydrin may help to relieve fissured fingertips, but sometimes a medium-potency corticosteroid ointment is required. If fissured fingertips are especially painful, the application of cyanoacrylate (Krazy Glue) can bring immediate relief, although patients can become sensitized to this compound over time.

Occasionally, oral antipruritic agents, such as the antihistamines, may be required for severe, generalized itching that results from xerosis (see Chapter 178). The physician should emphasize patient education to prevent recurrence.