Size of burn
If the burn area is larger than a silver dollar, see a doctor. In young children, even a smaller burn can be serious.
Location of burn
Hands, feet, face or genitalia are critical areas. A doctor should treat even small burns in these areas.
Age of injured
For infants, young children and the elderly, even small burns can be fatal.
Health of injured
Physical and mental impairments and conditions such as diabetes, etc. can complicate the injury.
Source of burn
Smoke inhalation, toxic fumes, electricity or chemicals all complicate a burn injury and require immediate medical attention.

The percentage of the body burned is determined by using a burn chart, such as the “rule of nines” burn chart.

This chart divides the body surface into areas, each of which represents 9 percent. The “rule of nines” is generally used for quick assessment of the total body surface area (TBSA) that has been injured. In infants and small children, the surface area of the head and neck is greater and the lower extremity is smaller than an adult. Therefore, the Lund-Browder chart more accurately determines the extent of a burn.

Burn Type

Thermal:
Flame, Flash,
Scalds
Scalds with viscous oils will be more severe than with hot water. Hot oils have greater thermal energy than does hot water because the flash point is higher. Thus hot oils can reach temperatures into the 2000C range and still remain liquid.

Electrical:
Electrical burns are particularly deceptive as the external injury may appear small but the destruction to underlying soft tissue, muscle and even bone may be quite severe.  Any electrical burn requires immediate specialty attention in an emergency room.

Chemical:
Acid burn:
damage to the body caused by a strong acid. The type of burn depends on the kind of acid and the length of time and amount of tissue exposed. Emergency treatment includes washing the area with large amounts of water.
Alkali burn:
tissue damage caused by an alkaline compound, as lye. Treatment includes flushing with water to wash off the chemical. Then vinegar or another mildly acidic substance mixed with water is put on the burn to make neutral any alkali that is left and to lessen the pain. The patient should be taken right away to a hospital or other treatment center if the damage is severe.