Dry skin  Dry skin. Simple dry skin — the kind you get in winter when the air is cold and rooms are overheated — is by far the most common cause of  itchy, flaking skin. But flakes from dry skin are generally smaller and less than those caused by dandruff

Definition  Ordinary dry skin (xerosis) usually isn't serious, but it can be uncomfortable and unsightly, turning plump cells into shriveled ones and creating fine lines and wrinkles. More serious dry skin conditions, such as the inherited group of disorders called ichthyosis, can sometimes be disfiguring enough to cause psychological distress.

 Fortunately, most dry skin results from environmental factors that can be wholly or partially controlled. These include exposure to hot or cold weather with low humidity levels, long-term use of air conditioning or central heating, and excessive bathing.  Chronic or severe dry skin problems may require a dermatologist's evaluation. But first you can do a lot on your own to improve your skin, including using moisturizers, bathing less and avoiding harsh, drying soaps.

Symptoms  Dry skin is often just a temporary problem — one you experience only in winter, for example — but it may be a lifelong concern. And although skin is often driest on your arms, lower legs and the sides of your abdomen, this pattern can vary considerably from person to person. What's more, signs and symptoms of dry skin depend on your age, your health status, your locale, the amount of time you spend outdoors, and the cause of the problem.  If you have dry skin due to normal aging, you're likely to experience one or more of the following:

 A feeling of skin tightness, especially after showering, bathing or swimming  Skin that appears shrunken or dehydrated  Skin that feels and looks rough rather than smooth  Itching (pruritus) that sometimes may be intense  Slight to severe flaking, scaling or peeling  Fine lines or cracks  Redness  Deep fissures that may bleed.  (pruritus, pain, itching and inflammation sometimes lead to bacterial infection,also roughness, flaking,loss of flexibility elasticity, fissures and hyperkeratosis.

Causes  Most dry skin is caused by environmental exposures, such as:  Weather. In general, your skin is driest in winter, when temperatures and humidity levels plummet. Winter conditions also tend to make many existing skin conditions worse. But the reverse may be true if you live in desert regions, where summer temperatures can top 110 F and humidity levels sink to 10 percent or less.  Central heating and air conditioning. Central air and heating, wood-burning stoves, space heaters and fireplaces all reduce humidity and dry your skin.

 Hot baths and showers. Frequent showering or bathing, especially if you like the water hot and your baths long, breaks down the lipid barriers in your skin. So does frequent swimming, particularly in heavily chlorinated pools.  Harsh soaps and detergents. Many popular soaps and detergents strip lipids and water from your skin. Deodorant and antibacterial soaps are usually the most damaging, as are many shampoos, which dry out skin.  Generally the cardinal sign is the decrease the moisture content of the stratum corneum than 10%

 Other factors Other factors, including certain diseases, can significantly alter the function and appearance of your skin. These include:  Psoriasis. This skin condition is marked by a rapid buildup of rough, dry, dead skin cells that form thick scales.  Thyroid disorders. Hypothyroidism, a condition that occurs when your thyroid produces too little thyroid hormones, reduces the activity of your sweat and oil glands, leading to rough, dry skin.  Alcohol and drugs. Alcohol and caffeine can visibly dry your skin. Prescription drugs such as diuretics, antihistamines and isotretinoin (Accutane

Risk factors  Dry skin is a nearly universal problem, but certain factors make you more likely to develop tightness, flakiness and fine lines. These factors include:  Your age. As you age, your skin tends to become drier because your oil-producing glands become less active. Your complexion can appear rough and dull. The lack of oil also causes cells to clump together in flakes or scales.  Your sex. Although everyone's skin changes with age, a man's skin tends to stay moist longer than a woman's does. Men experience a relatively small decrease in oil production until well into their 80s, whereas women's skin tends to become much drier after menopause

 Sun exposure. Like all types of heat, the sun dries your skin. Yet damage from ultraviolet (UV) radiation penetrates far beyond the top layer of skin (epidermis). The most significant damage occurs deep in the dermis, where collagen and elastin fibers break down much more quickly than they should, leading to deep wrinkles and loose, sagging skin (solar elastosis). Sun-damaged skin may have the appearance of dry skin.

 When to seek medical advice  Most cases of dry skin respond well to self-care measures. See your doctor if:  Your skin doesn't improve in spite of your best efforts  Dryness and itching interfere with sleeping  You have open sores or infections from scratching  You have large areas of scaling or peeling.

Treatments and drugs  In most cases, dry skin problems respond well to self-care measures, such as using moisturizers and avoiding long, hot showers and baths. very dry and scaly skin, doctor may recommend the use of an over-the- counter (nonprescription) cream that contains lactic acid or lactic acid and urea.

. Moisturizers provide a seal over skin to keep water from escaping.   If skin is extremely dry, apply an oil, such as baby oil, while the skin is still moist.  Oil has more staying power than moisturizers do and prevents the evaporation of water from the surface of the skin.

 Use warm water and limit bath time. Hot water and long showers or baths remove oils from your skin. Limit your bath or shower time to about 15 minutes or less, and use warm, rather than hot, water.  Avoid harsh, drying soaps. If you have dry skin, it's best to use cleansing creams or gentle skin cleansers and bath or shower gels with added moisturizers. Choose mild soaps that have added oils and fats,, . Avoid deodorant and antibacterial detergents, which are especially harsh. or dry.

 Choose fabrics that are kind to the skin. Natural fibers such as cotton and silk allow skin to breathe. But wool, although it certainly qualifies as natural, can irritate even normal skin.

FACTOR influencing water loss from the skin FACTOR influencing water loss from the skin  Temp.and humidity  Contact with non aqueous solvents and surfactants(removal of the NMF whch has the ability to retain water  Physical damage(burns  Age decreases the capacity of the sc to retain moisture

 Treatment  The main objectives in treating a dry skin are to raise the level of moisture in the stratum corneum and to reestablish the integrity of this layer  They showen that water is the only plasticizer for the corneum, but simply adding water to the skin without corneum to retain it, is not a useful approach

 Approach to treat dry skin.  Treat physiological water loss by applying a film of oil on to the skin, so decreasing the evaporation of endogenous water and rehydration follow.  Using water containing emollientsO/w emulsion, hydrate skin by their water content of product either by:  Evaporation and leave oil to act as occlusive  Or absorb water and remaining oil acts as occlusive

 OTC drugs  Urea and allantoin 10-30%,soften the keratin by disrupting its structure i.s mild keratolytic and moisturizer.  Glycerin 50 % in rose water: attract water from atmosphere and serves as a reservoir to supply water to the stratum corneum, also increase rate of transepidermal water loss so accelerate the diffusion of moisture from the dermal tissue  to the surface and holds water in intimate contact with the skin, also lubricate the skin.  Anhydrous lanoline  bees wax and spermaceti  Petrolatum  Iso propyl myristate

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