What is an Allergic Rash?

An allergic rash is a common physical response to an antigen that can result in redness, flaky skin, itching, and hives. People usually develop rashes after coming into direct contact with substance to which they are allergic, such as poison ivy or latex. Hives can also appear as an allergic reaction to medications, foods, insect stings, or airborne pathogens. A mild allergic rash can often be alleviated at home by applying topical lotions and antihistamine creams, though severe reactions often need medical treatment. Doctors can determine the cause of an allergic rash, prescribe medication, and explain how to avoid future reactions.

The immune system is responsible for fighting off dangerous bacteria and viruses in the body. An allergic person's immune system responds to allergens in the same way, even though the substances do not normally pose a threat to health. The release of natural antibodies causes the skin to become irritated, red, and inflamed, a condition known as eczema. In the case of hives, itchy blisters can appear in an isolated area or all over the body. In severe cases, eczema and hives can persist for several hours or even days after being exposed to an allergen.

A contact rash typically appears shortly after exposure to offensive chemicals, plant oils, or insect stings. Common sources of contact allergic rashes include poison ivy and sumac, perfumes, chlorine, and laundry detergents. Many people experience hives after taking certain medications, eating foods such as nuts and shellfish, or breathing in airborne allergens like pollen and animal dander.

Most allergic rashes can be relieved by avoiding the cause, cleaning the skin with cool water and mild soap, and applying a soothing ointment. Calamine lotion and topical antihistamines can significantly reduce burning and itching sensations. Many people take over-the-counter oral antihistamines as well to further reduce symptoms. A person who experiences frequent allergic reactions can talk to his or her doctor about long-term solutions, such as daily preventive medication or allergy shots.

A severe allergic rash can result in unbearable pain, swelling in the throat, fever, and nausea. Emergency medical care is necessary to prevent the individual from going into shock or slipping into unconsciousness. A doctor or emergency responder can inject the person with a shot of epinephrine to relieve throat swelling and stabilize blood pressure. During recovery, doctors explain what caused the allergic rash and inform the patient how to handle future incidences. Patients are often given their own supplies of epinephrine to have on hand should another episode occur.