Hydrofluoric Acid Burns Clinical Presentation

Updated: Jun 23, 2021
  • Author: Garry Wilkes, MBBS, FACEM; Chief Editor: Joe Alcock, MD, MS  more...
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Time of exposure to onset of symptoms is related to the concentration of the hydrofluoric (HF) acid, as follows:

  • Solutions of 14.5% and higher concentrations immediately produce symptoms.

  • Solutions of 12% may take up to an hour to produce symptoms.

  • Solutions of less than 7% may take several hours before onset of symptoms, resulting in delayed presentation, deeper penetration of the undissociated hydrofluoric acid, and a more severe burn.

  • Concentrated solutions cause immediate pain and produce surface burns similar to those produced by other common acids (eg, erythema, blistering, necrosis).

Pain typically is described as deep, burning, or throbbing. Pain often is disproportionate to apparent skin involvement.

Obtain a history of potential exposure to cleaning solutions within the last 24 hours, to include the following:

  • Duration and type of exposure - Skin, ophthalmic, gastrointestinal (vomiting, abdominal pain), and pulmonary (throat burning, dyspnea)

  • Concentration of acid

  • Use of protective measures

  • Other agents in the solution

  • Symptoms of hypocalcemia - Tetany, Chvostek sign, Trousseau sign

  • Cardiac arrhythmias

  • Additionally, obtain history of medications and intercurrent illness that predispose patient to hypocalcemia or hypomagnesemia.


Physical Examination

Weaker solutions penetrate before dissociating. Surface involvement in these cases is minimal and may be absent. [6]

Three categories of appearance include the following:

  • Grade 1 - A white burn mark and/or erythema and pain; a grade 1 burn is shown in the photo below

    Grade 1 hydrofluoric (HF) acid burns of the finger Grade 1 hydrofluoric (HF) acid burns of the fingertips. The patient has severe pain (maximum middle digit) with only minimal redness of the nail beds.
  • Grade 2 - A white burn mark and/or erythema and pain, plus edema and blistering

  • Grade 3 - A white burn mark and/or erythema and pain, edema, and blistering, plus necrosis; a grade 3 burn is shown in the photo below

    Grade 3 hydrofluoric (HF) acid burns of the finger Grade 3 hydrofluoric (HF) acid burns of the fingertips. Note how the nailbed and tip of the fingers have severely been injured, but the nails show no damage.

Patients with inhalation burns may develop acute lung injury presenting with the following:

  • Hypoxemia

  • Stridor

  • Wheezing

  • Rhonchi

Ocular burns may present with severe pain.



Complications are as follows:

  • Airway compromise

  • Systemic fluorosis

  • Acute lung injury/noncardiogenic pulmonary edema

  • Electrolyte abnormalities

  • Arrhythmias and cardiac arrest

  • Scarring

  • Loss of digits

  • Blindness