First-degree burns (superficial) are minor and heal fast.
Indicators: red and dry, no blisters.
Examples: sunburn, scald (from hot liquids), and flash flame.
Second-degree burns (partial thickness) may require immediate medical attention.
Indicators: moist blisters
Examples: contact with hot liquids or solids, flash flame, chemicals.
Third-degree burns (full thickness) are extremely serious and require immediate medical treatment.
Indicators: charred tissue, dry and leathery.
Examples: contact with hot liquids or solids, flames, chemicals, or electrical.
Fourth-degree burn - This term is not yet official, but many doctors use it when referring to bone burns.
Fourth-degree burns effect all layers of skin as well as the bone and are identified by charring of the bone.