Along with its vital roles as shield against microorganisms and regulating body temperature, skin often provides information about overall health and a variety of medical conditions. The color, texture, temperature, and elasticity of skin can aid in diagnosing a variety of disorders. For example, patients with hepatitis may have a characteristic yellow tinge to their skin. Similarly, cold sores and fever blisters are indications of infection with herpes simplex virus, and warts (intraepidermal skin tumors) result from infection with human papilloma virus (HPV).
Skin testing is an important diagnostic tool in the evaluation of allergies. Skin testing involves a series of superficial injections of one or more suspected allergens. A positive response, such as redness, or inflammation, at the site of the skin test, helps to pinpoint the culprit.
Common diseases and disorders
Acne, caused by clogged pores and bacterial infection, is commonly diagnosed in teenagers and young adults. Acne may be mild, moderate, or severe and is characterized by blackheads, whiteheads, papules, pustules, and cysts on the face, shoulders, chest, and back. Mild acne may be treated with topical antimicrobial agents to kill the bacteria on the skin and topical retinoids to open the pores. Moderate and severe acne often respond to treatment with systemic antibiotics such as tetracycline or doxycycline.
Common bacterial skin infections are impetigo, folliculitis, and cellulitis. Impetigo is a contagious skin infection caused by streptococci or staphylococcus. It produces crusty patches on the skin. Local outbreaks may be treated with antibacterial ointment, and patients with widespread infections are given oral antibiotics. Infectious folliculitis produces erythema (redness) and pustules. It is caused by staphylococcus and treated with oral antibiotics. Cellulitis is swelling, erythema, warmth, and pain caused by infection of the dermis and subcutaneous tissue often near a wound site. Cellulitis is usually caused by Group A streptococci or staph aureus and is treated with a course of anti-strep or anti-staph antibiotics.
Skin reactions include eczema, allergic contact dermatitis (rashes), such as those resulting from contact with poison ivy, sumac, or oak, and hives. Contact dermatitis, an eruption of itchy skin vesicles, is an allergic skin reaction. Patients are advised to avoid contact with the suspected allergen, and mild cases may be treated with warm soaks and topical ointments to reduce inflammation and soothe inflamed skin.
Cosmetic damage as well as potentially fatal skin disorders may result from overexposure to the ultraviolet (UV) rays in sunlight. At first, overexposure to sunlight results in injury known as sunburn. UV rays damage skin cells, blood vessels, and other dermal structures. Continual overexposure produces leathery skin, wrinkles, and discoloration and may also lead to skin cancer. Anyone excessively exposed to UV rays runs a risk of skin cancer, regardless of the amount of pigmentation normally in the skin. Seventy-five percent of all skin cancers are basal cell carcinomas that arise in the epidermis and rarely metastasize (spread) to other parts of the body. Physicians can surgically remove basal cell cancers. Squamous cell carcinomas also occur in the epidermis, and these may metastasize. Malignant melanomas are life-threatening skin cancers that metastasize rapidly. There can be a 10 to 20 year delay between exposure to sunlight and the development of skin cancers.
Dermatology is the medical specialty devoted to the diagnosis and treatment of skin disorders. In addition to the disorders previously described, primary care physicians and dermatologists are frequently called upon to diagnose and treat the following conditions:
vitiligo (loss of skin color on patches of skin, usually affects the face and extremities)
Today, many dermatologists also provide a range of cosmetic services to reduce the signs of aging, such as wrinkles, sagging skin and discoloration, and reverse some of the effects of sun damage to skin. Microdermabrasion, laser skin resurfacing, and injections of collagen are among the techniques used to improve the appearance of skin.
Barbara Wexler, The Gale Group Inc., Gale, Detroit,