Diseases and Disorder of the Skin

Any component of the skin can become involved in a variety of different diseases. The skin can often provide doctors with clues about the health of the body, since many diseases that affect other organ systems are evident as telltale clues on the skin. For example, a rash, such as that typical of measles or chicken pox, can indicate an infection that affects the whole body. A blue tinge to the skin, called cyanosis, means that the body is not getting enough oxygen and can indicate heart failure. A yellow tinge to the skin, known as jaundice, signals that the liver is not working properly. Other diseases are specific to the skin itself. These disorders range from the merely annoying or distressing, such as acne, to the potentially life-threatening, such as skin cancer.

In response to various triggering substances, or allergens, immune cells known as mast cells in the skin may release a chemical called histamine. Other immune cells called T cells may directly damage the epidermis. These events can result in either of two skin disorders, eczema or hives. Eczema is a red, scaly rash that commonly occurs in body folds such as in front of the elbow, behind the knee, and around the groin. It can usually be controlled with oral antihistamines and cortisone creams. Hives, also called urticaria, are red, raised, weltlike lesions on the skin, often occurring on the face and neck. Hives are often triggered by ingestion or inhalation of a substance, such as a medication or food, to which a person is allergic. Therefore, the most effective way of controlling hives is to recognize and avoid future contact with the allergen. Occasionally, hives may be an indication of a more serious, even life-threatening allergic reaction. In such situations, the airways can become constricted, making breathing difficult, and rapid intervention with injections of adrenaline may be required.