Necrotic Spider Or Tick Bite? Warning Against Dermal Therapies Using Heat Or Other Vasodilator (Disease/Disorder Overview‪)‬

[ILLUSTRATION OMITTED] Spider bites and tick bites need careful diagnostic differentiation in clinical and forensic investigation, particularly if associated with severe systemic illness. This article, continuing part I of the Winter 2007 issue of The Forensic Examiner, compares envenomation by brown spiders (Sicariidae), six-eyed crab spiders (Sicariidae), and sac spiders (Clubionidae) to tick-transmitted or other zoonotic illnesses, including babesiosis (with notes on Rocky Mountain spotted fever), Lyme disease, tularemia, EboLa hemorrhagic fever, and African tick-bite fever. Spider bites, compared to tick bites, are more readily necrotic and present sooner with systemic symptoms. Vasodilation therapies, facilitating the venom's entry into the blood at bite sites, are warned against.