Experimental 70% hydrofluoric acid burns: histological observations in an established human skin explants ex vivo model

BACKGROUND Hydrofluoric acid (HF) is particularly dangerous due to the potential for systemic effects and induction of severe skin necrosis through two mechanisms: corrosiveness and local tissue toxicity. In addition, because it is only partially dissociated (pK(a) 3.2), it is capable of penetrating deeply into tissues. There is a lack of experimental studies that objectively characterize the behavior of HF diffusion into human skin, specifically the kinetics of tissue penetration resulting in severe cellular lesions. METHODOLOGY/PRINCIPAL FINDINGS We describe the cutaneous effects of HF using an established ex vivo human skin model. The diffusion of 70% HF starts within the first minute of contact at the epidermal surface and after 2 min reaches the basal layer. In the subsequent minute, the epidermis is destroyed and lesions appear in the papillary dermis after 4 min. Soon after, damage appears in the upper reticular dermis. Thus, 70% HF needs only 5 min of contact to completely penetrate human skin explants. This experiment is reproducible and corroborates previous studies and clinical effects reported in accidental HF exposures. CONCLUSION/SIGNIFICANCE This study shows that the management of HF chemical skin exposure is a question of minutes, especially for initial decontamination. These experimental observations could be useful for objectively comparing skin decontamination methods. Further studies should help to confirm these preliminary results.