So the definitive diagnosis can be difficult. Other considerations in the differential diagnosis include other insect bites, trauma, cellulitis, vasculitis, thrombangitis obliterans, arterial emboli, drug reactions and pyoderma gangrenosum. Also included are diabetic neurocutaneous dystrophy, epidermoid cancer in situ , epidermolysis bullosa and factitial ulceration. The medical literature is full of experimental and controversial therapies for the BR spider bite. It is generally agreed that uncomplicated localized cutaneous arachnidism only requires conservative management, consisting of good wound care, elevation and immobilization of the affected extremity, topical antibiotics and daily wound dressings.
Tetanus prophylaxis is recommended, but the role of prophylactic systemic antibiotics is debatable.
Antivenom, given within the first 24 hours could theoretically reduce the incidence of dermatonecrosis, but it is neither FDA approved nor commercially available. Experimental trials with local electric shock therapy can even be found in the literature. Dapsone has been a popular experimental therapy in animal models and has been advocated for human use. The theoretical basis of this agent lies in inhibiting the PML aggregation at the wound site and causing tissue necrosis. However promising, most results are anecdotal and no large double-blind controlled study exists to prove its efficacy.