Skin

Also known as atopic dermatitis, affects between 10 and 20 percent of children and 1 to 3 percent of adults. A common symptom of eczema is dry, red, irritated and itchy skin. Sometimes, especially when infected, the skin may have small, fluid-filled bumps that ooze a clear or yellowish liquid. People with eczema often have a family history of allergies.

Also referred to as urticaria, are red bumps or welts that appear on the body. The condition is called acute urticaria if it lasts for no more than six weeks, and chronic urticaria if it persists beyond six weeks. Acute urticaria is most commonly caused by exposure to an allergen or by an infection. The cause of chronic urticaria is largely unknown.

A reaction that appears when skin comes in contact with an irritant or an allergen. Symptoms can include a rash, blisters, itching and burning. Soaps, laundry detergents, fabric softeners, shampoos, latex gloves, adhesives, medications, perfumes, lotions, plants, grass — or even excessive exposure to water or sun — can all cause contact dermatitis.