latrodectism latrodectism latrodectism (/lætrəˈdɛktɪzəm/) is the illness caused by the bite of latrodectus spiders (the black widow spider and related species). pain, muscle rigidity, vomiting, and sweating are the symptoms of latrodectism. latrodectismthe southern black widow spider (latrodectus mactans), a cause of latrodectismspecialtyemergency medicine there are several spider species all named black widow: southern black widow spider (l. mactans), the european black widow (l. tredecimguttatus), western black widow spider (l. hesperus), northern black widow spider (l. variolus). other latrodectus that cause latrodectism are the australian redback spider (l. hasselti), the new zealand katipō spider (l. katipo) and the south american latrodectus corallinus and latrodectus curacaviensis. several other members of the genus latrodectus are not commonly associated with latrodectism including the cosmopolitan brown widow (l. geometricus). signs and symptoms symptoms of a bite depend on the amount of venom injected. a bite of latrodectus may not inject any venom (known as a dry bite) and so no illness occurs. about 75% of "wet" bites will have localized pain and nothing more. if, however, there is a substantial dose, a bite can cause latrodectism. the main symptoms are generalized muscle pain, stomach cramps, nausea and vomiting. initially a pinprick or burning sensation can be felt when bitten by widow spiders. if there was enough venom injected, pain worsens over the next hour. the area will develop localized sweating and gooseflesh piloerection. the pain may spread and become generalized. the typical duration is three to six days. rarely, some people who do not receive antivenom may have muscle weakness that lasts for weeks. classic course intense local pain develops 5–10 minutes after the bite and is followed by sweating and piloerection (goosebumps) within an hour. neither puncture marks nor redness are necessarily seen. a few people go on to have widespread symptoms. pain typically starts at the bite site then travels up (e.g. from foot to thigh to trunk), followed by generalized pain (in back, trunk, chest or shoulder). the venom directly affects nerves leading to the unusual feature of severe sweating, which may be regional (e.g. one leg). changes in adrenaline can lead to mild increase in blood pressure and pulse. non-specific features of latrodectism include headache, nausea, vomiting and feeling ill and weak. symptoms may wax and wane over the next one to four days. rarely, patients may feel unwell for up to a week. very rarely, untreated patients report ongoing bite site pain that last weeks or months. special circumstances during pregnancy the pain and abdominal cramps may be confused with other conditions. a case of preterm labor initiated by a redback spider was relieved by antivenom. early medical reports of latrodectism were described in men using outhouses. the genitals were often the site of the bite. no direct injury to site is reported. myocarditis (inflammation of the heart muscle) has been associated with one medically reported death in the last 50 years. rhabdomyolysis (rapid skeletal muscle tissue breakdown) is an uncommon complication. pathophysiology