Fig. 1. Burn depth.

Burn depth is an important factor in assessing patient care needs and, in particular, surgical needs; in general, the deeper the burn the more challenges there are to achieve good scar outcomes. First-degree (superficial thickness, affecting the epidermis only) burns are typically benign, very painful, heal without scarring and do not require surgery. Burns extending into the underlying skin layer (dermis) are classed as partial thickness or second-degree; these burns frequently form painful blisters. These burns range from superficial partial thickness, which are homogeneous, moist, hyperaemic and blanch, to deep partial thickness, which are less sensate, drier, may have a reticular pattern to the erythema and do not blanch. Third-degree (full thickness) and fourth-degree burns require surgery and, paradoxically, usually present with almost no pain.