Topical exposure to hydrofluoric acid can result in severe burns. The severity and extent of the burn depends on the concentration of the acid, the area exposed, and duration of contact.
Features of hydrofluoric acid burns:
(1) extreme pain that may persist for days if untreated
(2) coagulation of the skin and subcutaneous tissue at the burn site
(3) progressive tissue destruction
(4) if hands or feet exposed, predilection for subungual areas
(5) systemic intoxication with high HF concentrations, inhalation, ingestion and/or large body surface area (>= 160 square cm) exposures
where:
• 160 square cm is about the area subtended by 2 palm-sized areas of an adult and may represent 1-2% BSA in an adult.
Concentration of HF
Onset of Symptoms
<= 20%
delayed (24 hours after the exposure)
20 - 25%
within 1-8 hours
26 - 50%
less than 1 hour, with interval decreasing as concentration increases
> 50%
immediately, with rapid tissue destruction
Skin changes may range from mild erythema to third degree burns. Typically the burn site is indurated and whitish, surrounded by erythema. Vesicles and bullae are common.
