The Adjuvant Effect of Hyperbaric Oxygenation for Loxosceles rufescens Bite: A Case Series.

Background: The venom of Loxoscelesrufescens (L.r.), also known as the violin and/or brown spider, contains a wide variety of proteins and can induce a complex, intense, and uncontrolled inflammatory response, hemolysis, thrombocytopenia, dermo-necrosis, and renal failure. Studies have postulated the efficacy of hyperbaric oxygen therapy (HBOT) for Loxosceles bites. However, data describing the use and beneficial effects of HBO are, to date, relatively scarce. Only a few cases of Loxosceles bites in Northern Italy have been documented, and there is no laboratory test available for the diagnosis.

Objectives: We present seven cases (aged 54.5 ± 4.2 years) of patients who presented to the emergency room (E.R.) of Niguarda Hospital in Milan from March to October 2022.

Methods: Blood and urine samples were collected and biomarkers of oxidative stress (OxS) (reactive oxygen species (ROS), total antioxidant capacity (TAC), lipid peroxidation (8iso-PFG2α), DNA damage (8-OH-dG)), inflammation (IL-6, IL-1β, TNF-α, sICAM1), and renal function (creatinine, neopterin, uric acid) before (T0), during (T1, T2), and after (1-2 wk T3-T4; 1 month T5) the HBOT treatment (US Navy Treatment Table 15 protocol) were studied.

Results: At T0, patients showed a significant unbalance of OxS; high levels of ROS, 8-isoPGF2α, and inflammatory status (IL-6, TNF-α; sICAM); and a low level of antioxidant capacity. At the end of HBOT (T2), a significant reduction in Oxy-inflammation levels over time-8-iso -26%, 8-OH-dG -9%, IL-6 -71%, IL-1bβ -12%, TNF-α -13%, and sICAM1 -17%-associated with clinical improvement was shown.

Conclusions: These reductions, along with those in renal function markers, mirrored the observed improvement in the evolution of the skin lesion and the patients' self-reported general wellness and pain. In conclusion, HBOT should be considered a valuable therapeutic tool after L.r. bites.