Skin allergy can be defined as swollen, bumpy, itchy, red, or scaly skin. An immune system reaction often causes these skin problems. Skin allergy is due to various causes and can take several forms.

Some of the most common skin allergy forms are discussed in the following.

Hives:

Hives or urticania are swollen, red, itchy areas of the skin that appear anywhere on the body and can range in size. About 25% of the U.S. population will experience an episode of hives at least once in their lives. Acute hives are the most common and are caused by identifiable-often viral infection, latex, drug, or food. Acute hives typically go away spontaneously as compared to chronic hives, which occur almost daily for months to years.

Angioedema:

Sometimes occurs with hives, angioedema is a swelling of the deeper layers of the skin. It is not itchy or red, and soft tissues like genitals, mouth, or eyelids are the body areas where it often occurs.

Important Note:

The above two forms of skin allergy may appear together or separately on the body. Actions of a chemical known as histamine in the deeper layers of the skin cause angioedema, and on the other hand, actions of the chemical in the upper layers of the skin cause hives.

In mast cells that heavily involved in allergic reactions, these chemicals are usually stored. Histamine is released by several identifiable triggers and other chemicals from the mast cells, causing hives.

Contact Dermatitis:

Contact dermatitis is a rash due to coming in contact of the skin with some substances. Some of these reactions are the result of an allergic reaction that involves the immune system. However, non-allergic or irritant reaction also causes many of these reactions. Telling the difference between these two types of reactions is often quite difficult. Contact dermatitis occurs almost exclusively where the offending agent such as a plant or chemical comes in contact with the skin.