Some medicines for the skin require a prescription, others can be purchased without a prescription. Although generally are considered safer than those that require a prescription, OTC medicines should be used with caution. Implementing the wrong medication can worsen a disease skin or hide symptoms, making diagnosis more difficult for the doctor.

Topical preparations
The active substances (drugs) from a topical preparation are mixed with (suspended in) a vehicle (an inert carrier of the medication). . Consequently, among the topical preparations, the formulation and consistency vary widely. It is the vehicle that determines the strength of the product and makes the active compounds remain on the surface or penetrate the skin (if the preparation is thick and oily and watery or light). Depending on the vehicle used, the preparation will be an ointment, cream, lotion, a solution, a powder or a gel.

Ointments, which contain a large amount of oil and very little water, have a greasy appearance and are difficult to wash. Ointments are more appropriate when the skin requires lubrication or moisture. While its use is more cumbersome that preparations with water-based creams, ointments are more effective in providing active ingredients to the skin.

The creams, which are the most commonly used preparations are oil in water emulsions. They are easy to apply and give the feeling of disappearing scrub on the skin.

Lotions are similar to creams but they contain more water. They are in fact suspensions of finely powdered material dispersed in a water-based or oil and water. Lotions are easy to use and are particularly beneficial to the `cool or dry skin.
The solutions are liquid in which a drug dissolves. The solutions tend to dry the skin rather than moisten. Liquids are most frequently used alcohol, propylene, polyethylene and running water.
The powders are dried forms of substances that are used to protect areas where skin rubs a region against another (for example, in the buttocks, between the toes, in the armpits or groin, or under the breasts ). Powders dry skin macerated (softened and damaged by moisture) and reduce friction by absorbing moisture.. Powders can be incorporated into the protective creams, lotions and the ointments.

The gels are water-based substances with a thickened without oil or fat.The skin does not absorb the gels as well as preparations containing oil or grease.

Each layer of the skin meets a specific task. The outer layer, the epidermis, is finer, in most parts of the body, a plastic film. The top of the epidermis, the stratum corneum, containing keratin, is made up of remnants of dead cells and protects the skin from harmful substances. At the bottom of the epidermis are the melanocytes, cells that produce melanin (the dark pigment of the skin).

Beneath the epidermis is located the dermis, which contains pain and touch receptors, whose ramifications reach the surface of the skin and various glands function of the same: sweat glands, which produce sweat, sebaceous glands, which produce tallow, and hair follicles, which cause hair. Also, inside the dermis, are blood vessels that provide nutrients and heat to the skin and nerves that branch off between the different layers of the same.

Below the dermis is a layer of fat that helps insulate the body of heat and cold.

In the various regions of the body vary the thickness and color of the skin, and the number of sweat glands, sebaceous glands, hair follicles and nerves. The top of the head has a large quantity of hair follicles, while the palms and soles of the feet do not have them. The layers of keratin and skin are thicker on the soles of the feet and the palms of their hands. The fingertips of the hands and feet are highly innervated and are extremely sensitive to the touch.

The skin tends to undergo changes throughout a person’s life. The skin of a baby has a thicker layer of fat and a lot more fine-protective keratin. As people get older lose their subcutaneous fat layer, the epidermis and dermis become thinner, elastic fibers in the dermis fragment and the skin tends to wrinkle. The blood of the skin also decreases with age, so that the skin lesions heal more slowly in older people. The skins aging produce more sebum less protective and so the skin dries out more easily.

Diagnosis of skin diseases
Doctors can identify many diseases of the skin through a simple visual scan. Features include revealing size, shape, color and location of the anomaly, as well as the presence or absence of other signs or symptoms. Sometimes the doctor must remove a small piece of skin for examination under a microscope, this method is called a biopsy. For this simple operation, the doctor, usually desensitized a small area of skin with a local anesthetic and, using a scalpel ( scalpel) or a circular punch (punch biopsies), removes a piece of skin of about three millimeters in diameter. Often the doctor closed the cut with a point and stop the bleeding.

When doctors suspect that the skin can be infected, made a scraping of the material and send it to a laboratory where the specimen is planted in a culture medium. If the sample contains bacteria, fungi or viruses, they grow the crop, and may well be identified.

Other laboratory tests can also assist physicians in diagnosing infections of the skin. In light of a review with Wood, a frequency of ultraviolet light (black), some fungi are visible, as well as certain anomalies of pigmentation. The analysis helps diagnose viral infections of the skin such as herpes. With a small scalpel, the doctor scrapes the surface of the skin swollen and examines the microscope. If evidence is an enlargement or a cluster of cells, this may indicate a viral infection.The sample of skin may also be sent to a laboratory to conduct a crop for the virus.
 

Many of the problems in the skin are limited to it.  However, in some cases, the skin indicates an alteration of any part of the body. Doctors should consider when evaluating several possible causes of skin problems.  Examine the skin surface in its entirety and seek certain types of eruption could help them identify any disease. To examine the distribution of a skin problem, the doctor may ask the patient to undress completely, though the patient only noticed anomalies in a small area of skin. Doctors also can request a blood test or other lab tests but the person apparently has a problem that is limited only to the skin.