Allergies are the result of an abnormally sensitive immune system. Patients with allergies have an immune system that develops a strong reaction to normally harmless substances called allergens. One common symptom of an allergic reaction is skin itching. Although this condition is generally not life-threatening, it can cause significant discomfort.
Contact Dermatitis
Allergies cause itching of the skin via a condition known as contact dermatitis, the Mayo Clinic explains. Contact dermatitis causes inflammation of the skin as a result of contact with an irritating substance such as an allergen. Contact dermatitis is responsible for the skin symptoms of patients who have touched poison ivy or poison oak, for example. Contact dermatitis can also be caused by some fragrances, latex, cosmetics and other chemicals.
Symptoms
When allergies cause skin itching a rash can also develop, according to Medline Plus, a website of the National Institutes of Health. The affected area might become red and somewhat swollen. The affected skin can also become tender or feel slightly warm as a result of the inflammation. In extreme cases of contact dermatitis, blisters or small fluid-filled bumps may appear and ooze pus or other fluids.
Other Allergies
Other types of allergic reactions can also lead to skin itching, the American Academy of Allergy Asthma and Immunology (AAAAI) explains. Some food and drug allergies cause patients to develop hives, which can be extremely itchy. Other allergens can cause a condition known as eczema, in which affected parts of the skin develop an itchy and scaly rash. Eczema most commonly affects the face, knees and elbows, though it can occur anywhere on the body.
Diagnosis
One key aspect of treating allergies is determining the allergen that causes the reaction. Allergy skin tests, the Mayo Clinic explains, can be used to help diagnose skin allergies that lead to contact dermatitis. With an allergy skin test, small amounts of potential allergens are placed on the patients skin which is then pricked to allow the substance to get under the skin. If the patient is allergic to the suspected allergen, the skin will swell and turn red. This test is a simple and rapid way of identifying substances to which the patient is allergic.
Treatment
Allergies that lead to skin itching can be treated in a variety of ways. The simplest technique is to simply avoid contact with the allergen. Patients can also apply moisturizer or creams with aloe to relieve the itching. For severe skin itching and inflammation, topical corticosteroids can be applied. Antihistamines can also be utilized to minimize the allergic reaction.
