page_title: Snakebite
section_title: Signs and symptoms
hierarchical_section_title: Snakebite / Signs and symptoms
caption_attribution_description: Extensive Tissue Necrosis of the Lower Limb in an 11-Year-Old Boy who had been bitten two weeks earlier by a Bothrops asper (viper) in Ecuador. The degree of necrosis is sufficiently severe that some form of surgical amputation above the knee would have been inevitable.
context_page_description: A snakebite is an injury caused by the bite of a snake, especially a venomous snake. A common sign of a bite from a venomous snake is the presence of two puncture wounds from the animal's fangs. Sometimes venom injection from the bite may occur. This may result in redness, swelling, and severe pain at the area, which may take up to an hour to appear. Vomiting, blurred vision, tingling of the limbs, and sweating may result. Most bites are on the hands, arms, or legs. Fear following a bite is common with symptoms of a racing heart and feeling faint. The venom may cause bleeding, kidney failure, a severe allergic reaction, tissue death around the bite, or breathing problems. Bites may result in the loss of a limb or other chronic problems. The outcome depends on the type of snake, the area of the body bitten, the amount of venom injected, and the general health of the person bitten. Problems are often more severe in children than adults, due to their smaller size.
  Snakes adminster bites, both as a method of hunting, and as a means of protection. Risk factors for bites include working outside with one's hands such as in farming, forestry, and construction.
context_section_description: The most common first symptom of all snakebites is an overwhelming fear, which may contribute to other symptoms,  and may include nausea and vomiting, diarrhea, vertigo, fainting, tachycardia, and cold, clammy skin. Television, literature, and folklore may contribute to the fear surrounding snakebites, causing people to experience unwarranted thoughts of imminent death.
  Dry snakebites and those inflicted by a non-venomous species may still cause severe injury. The bite may become infected from the snake's saliva. The fangs sometimes harbor pathogenic microbial organisms, including Clostridium tetani. Infection is often reported from the bites of vipers, whose fangs are capable of deep puncture wounds, which may introduce infectious organisms into the tissue. Venom may cause anaphylaxis in certain people.
  Most snakebites, from either a venomous or a non-venemous snake, will have some type of local effect. Minor pain and redness occur in over 90 percent of cases, although this varies depending on the site. Bites by vipers and some cobras may be extremely painful, with the local tissue sometimes becoming tender and severely swollen within five minutes. This area may also bleed and blister, and may lead to tissue necrosis. Other common initial symptoms of pit viper and viper bites include lethargy, bleeding, weakness, nausea, and vomiting. Symptoms may become more life-threatening over time, developing into hypotension, tachypnea, severe tachycardia, severe internal bleeding, altered sensorium, kidney failure, and respiratory failure.
  Bites by some snakes, such as the kraits, coral snake, Mojave rattlesnake, and the speckled rattlesnake, may cause little or no pain, despite their serious and  potentially life-threatening venom. Some people report  experiencing a "rubbery", "minty", or "metallic" taste after being bitten by certain species of rattlesnake. Spitting cobras and rinkhalses can spit venom in a person's eyes. This results in immediate pain, ophthalmoparesis, and sometimes blindness.
  Some Australian elapids and most viper envenomations will cause coagulopathy, sometimes so severe that a person may bleed spontaneously from the mouth, nose, and even old, seemingly healed wounds. Internal organs may bleed, including the brain and intestines, and ecchymosis (bruising) of the skin is often seen.
  The venom of elapids, including sea snakes, kraits, cobras, king cobra, mambas, and many Australian species, contains toxins which attack the nervous system, causing neurotoxicity. The person may present with strange disturbances to their vision, including blurriness. Paresthesia throughout the body, as well as difficulty in speaking and breathing, may be reported. Nervous system problems will cause a huge array of symptoms, and those provided here are not exhaustive. If not treated immediately they may die from respiratory failure.
  Venom emitted from some types of cobras, almost all vipers and some sea snakes causes necrosis of muscle tissue. Muscle tissue will begin to die throughout the body, a condition known as rhabdomyolysis.  Rhabdomyolysis can result in damage to the kidneys as a result of myoglobin accumulation in the renal tubules. This, coupled with hypotension, can lead to acute kidney injury, and, if left untreated, eventually death.
caption: Severe tissue necrosis following Bothrops asper envenomation that required amputation above the knee. The person was an 11-year-old boy, bitten two weeks earlier in Ecuador, but treated only with antibiotics.[20]
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