Blister

A blister is a collection of fluid that forms underneath the top layer of skin, the epidermis. The fluid inside a blister can be serum, plasma, blood, or pus, depending on the cause and location. Blisters typically act as a protective cushion to prevent further damage to the deeper layers of the skin and allow healing.

Common causes of blisters include friction or rubbing (e.g., from ill-fitting shoes), burns, chemical exposure, freezing, infections, allergic reactions, and certain skin diseases such as chickenpox, herpes, eczema, and autoimmune conditions like bullous pemphigoid. Blisters can vary in size from tiny pinpricks to several centimeters and can be painful or itchy. It is generally advised to keep blisters intact to minimize the risk of infection, and proper hygiene is important for healing.

In summary, blisters are fluid-filled bubbles in or on the skin that develop as a response to injury, irritation, or disease, serving to protect underlying tissue and promote recovery.