A rash is a noticeable change in the skin's appearance, often characterized by redness, swelling, or irritation. Rashes can occur due to various factors, including allergies, infections, or skin conditions like eczema and psoriasis. They can appear anywhere on the body and may be itchy, painful, or cause discomfort. Rashes can be temporary or chronic, depending on their cause. Common types include contact dermatitis, which results from skin contact with irritants, and hives, which are raised welts often triggered by allergic reactions. Treatment varies based on the underlying cause and may include topical creams, antihistamines, or other medications.