Dry skin, also known as xerosis or xeroderma affects perhaps 75% of patients aged 6 years and older.
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. These results from a 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 the dermal capillaries. Erosions at this depth causes bleeding. Pruritus developing as a result of xerotic eczema is common with dry skin and may be severe. 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 (eg vesicles,urticaria).
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.
Patients with dry skin can choose from a host of products and interventions. The patients may pre-soak the area with warm water before applying emollients and /or moisturisers. 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. The net effect is softening of the skin. Ingredients in emollients include mineral oils (eg liquid paraffin, petrolatum), waxes (eg lanolin, beeswax, carnauba), long chain esters, fatty acids, mono –di-triglycerides.
Although the term “moisturiser” is often used interchangeably with emollient, moisturisers 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, glycerine and propylene glycol.