The immune system of an allergic person over-reacts to innocent substances, known as allergens. Substances such as pollen, milk, latex or jewelries and treats these as harmful. In the process, the body releases chemicals like histamine that cause allergic reactions. Histamine in the skin or bloodstream produces hives, swelling, itchiness or rashes. Allergy symptoms on the skin can be irritating and require medical treatment, but in themselves are not life-threatening.
Contact Dermatitis
Symptoms of contact dermatitis include itchy, red, blistered rashes that develop within 2 days after direct contact with the allergen. There may be pain or tenderness, severe itching, or red patches resembling burn marks on the affected areas of the skin. In severe cases, fluid drains out of the blisters and may become susceptible to infection. According to the Mayo Clinic, contact allergy to a specific substance persists for life. The most common triggers for allergic symptoms to appear on the skin are poison ivy, nickel, costume jewelry, cosmetics, latex, hair dyes, and certain drugs.
Eczema
Symptoms of eczema, also called atopic dermatitis, include red, scaly itchy rash that develop into thick, brown patches. The rashes are extremely itchy, irritating, and may lead to more scratching and therefore, itching. In infants, the rash appears over the cheeks, neck and scalp. In older children, eczema may appear on the inner forearm, behind the knees and opposite the elbows. Common triggers of eczema include dander, house dust mites, and certain foods. Eczema is common in infants and young children, and in persons with family history of allergy.
Hives
Hives, also called urticaria, are raised, red, itchy bumps or welts that appear randomly on the skin. Hives usually appear suddenly and last only a few hours. Hives are irritable but generally harmless and people usually only need antihistamines to relieve the itching. However, people with chronic hives may suffer for months to years, notes the American Academy of Allergy Asthma & Immunology. Common triggers for hives are food, pollen, animal dander, cold, heat, insect venom and emotional distress.
Angioedema
Large, swollen welts that develop in the deeper layers of the skin are called angioedema. Angioedema may feel itchy, tingling or burning, and sometimes painful when swelling occurs over joints. Commonly, swelling involves the face, lips, tongue and throat. Angioedema may require medical care if the swelling involves very large areas of the body, or causes the tongue or throat to swell and interferes with breathing. Angioedema and hives usually occur together and have the same triggers.
