Burns are classified into 4 degrees. They are ::
1. First-degree (superficial) burns. First-degree burns affect only the epidermis, or outer layer of skin.
2. Second-degree (partial thickness) burns. Second-degree burns involve the epidermis and part of the dermis layer of skin.
3. Third-degree (full thickness) burns.
4. Fourth-degree burns.
Blisters are a sign of Second-degree burns.
