The Brown Recluse Spider, Loxosceles Reclusa Gertsch And Mulaik

The brown recluse (Loxosceles reclusa Gertsch and Mulaik) is one of the few spiders of the south and central United States whose bite is poisonous to man. It is one of the 4 species of Loxosceles (laeta, gaucho, reclusa, and rufescens) known to be venomous, but probably the venoms of all of the species of the genus are toxic. The bite of the mature female, as in almost all spiders, is more potent than that of the male. Although the bite of L. Reclusa usually does not produce such serious and immediate reactions as does the systemic bite of the widow spiders (Latrodectus spp.), A disease, now called necrotic arachnidism or loxoscelism, is caused by its bite. Reactions to the bite vary from mild to very severe. Some victims may not even feel the actual bite, but within a few hours the bitten part usually becomes swollen and painful, and blisters may form on the skin around the bite. The skin at the bite site begins to turn purple, and eventually becomes black and dry as the cells die. Within a few weeks the blackened area flakes away, leaving a circular pit in the skin which fills with scar tissue. The sloughed area, often quite large (up to 30 mm in diameter), may persist for several weeks, and healing takes place very slowly over a period of several months. A skin graft may be required to prevent a permanent scar. Reaction in some persons may be much less severe, consisting only of a local and temporary irritation of the skin, but in others it may be much more severe. In some patients, systematic disturbance of a general nature has been indicated by a rash resembling that of scarlet fever. In a few persons, the venom of the brown recluse spider has caused the destruction of many red blood cells, a very serious complication, signaled by the appearance of bloody or dark-colored urine, according to Gorham (1970). The venom of Loxosceles contains powerful cytotoxins, neurotoxins, and haemotoxins. No antivenin is available. The administration of corticosteroids within 24 hours gives relief. Otherwise, no effective treatment has been found to arrest the necrosis before it has run its course or to promote healing after the dead tissue has sloughed. Treatment is directed at controlling the symptoms and limiting the amount of tissue destruction.