Itchy skin can be caused by various factors, including skin conditions, internal diseases, nerve disorders, psychiatric conditions, irritation, and allergic reactions. Allergic reactions can cause an itchy rash and are one of the most common causes of itchy skin. Allergens that can cause an allergic skin reaction include fragrances, nail polish, shampoos, latex, cement, and certain foods. Contact dermatitis is a common cause of itchy skin from allergies, which occurs when the skin comes into direct contact with an allergen or irritant. Allergic contact dermatitis can cause red, itchy bumps on the skin, especially at the site of contact. If you develop an allergic reaction, you should find out what’s causing your allergy so that you can stop touching or using what’s causing the itchy rash. This can be challenging and often requires the help of a dermatologist or an allergist.