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

Abstract

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 (pKa 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.