Rash 101: Introduction to Common Skin Rashes

• Rash is not a specific diagnosis. It is instead a general term that means an outbreak of skin inflammation and discoloration that change the way the skin looks and feels.
• Common rashes include eczema, poison ivy, and heat rash.
• Infections that cause rashes include fungal, bacterial, or viral infection.
• Over-the-counter products to combat infection or itch may be helpful with the proper diagnosis.
• Rashes lasting more than a few days that are unexplained should be evaluated by a doctor.

Common, noninfectious rashes are listed below. Since these conditions are not caused by infectious organisms, it is reasonable to attempt to treat them with over-the-counter 1% hydrocortisone cream for a week or so prior to seeking medical attention.

Seborrheic dermatitis: Seborrheic dermatitis is the single most common rash affecting adults. It produces a red, scaling eruption that characteristically affects the scalp, forehead, brows, cheeks, and external ears.

Atopic dermatitis: Atopic dermatitis, often called eczema, is a common disorder of childhood which produces red, itchy, weeping rashes on the inner aspects of the elbows and in back of the knees as well as the cheeks, neck, wrists, and ankles. It is commonly found in patients who also have asthma and hay fever.

Contact dermatitis: Contact dermatitis is a rash that is brought on either by contact with a specific chemical to which the patient is uniquely allergic or with a substance that directly irritates the skin. Some chemicals are both irritants and allergens. This rash is also occasionally weepy and oozy and affects the parts of the skin which have come in direct contact with the offending substance. Common examples of contact dermatitis caused by allergy are poison ivy or poison oak (same chemical, different plant) and reactions to costume jewelry containing nickel.

Diaper rash: This is a common type of contact dermatitis that occurs in most infants who wear diapers when feces and urine are in contact with skin for too long.

Stasis dermatitis: This is a weepy, oozy dermatitis that occurs on the lower legs of individual who have chronic swelling because of poor circulation in veins.

Psoriasis: This bumpy scaling eruption never weeps or oozes and tends to occur on the scalp, elbows, and knees. It leads to silvery flakes of skin that scale and fall off.

Nummular eczema: This is a weepy, oozy dermatitis that tends to occur a coin-shaped plaques in the winter time and is associated with very dry skin.

Source: MedicineNet.com
http://www.medicinenet.com/rash/article.htm