Spider Bite FAQ

Kyoto: Hiking from Kibune to Kurama

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Scorpions are found throughout most of the United States, but the species lethal for man, Centruroides, are limited to Arizona, New Mexico, Texas, southern California, and northern Mexico. In these areas scorpions are a significant problem. Sixty-nine deaths resulted from scorpion stings in Arizona between 1929 and 1954. During the same period, only twenty deaths resulted from poisonous snake bites. With improved medical management of the complications of scorpion stings, no deaths have occurred in Arizona for twenty years. Scorpions are eight-legged arachnids that range in length from three to eight inches (7.5 to 20 cm) and have a rather plump body, thin tail, and large pinchers. They are found in dry climates under rocks and logs, buried in the sand, in accumulations of lumber, bricks, or brush, and in the attics, walls, or understructures of houses or deserted buildings, The problems with scorpions in Arizona are clearly related to their tendency to live in the vicinity of human habitation where children are frequently playing.

Stings can be avoided by exercising care when picking up stones, logs, or similar objects under which scorpions hide during the day. Since scorpions are nocturnal, walking barefoot after dark is inadvisable. Shoes and clothing should be shaken vigorously before dressing in the morning, particularly when camping outdoors.

The lethal species of scorpions are often found under loose bark or around old tree stumps. They have a yellow to greenish yellow color and can be distinguished from other species by a small, knob-like projection at the base of their stingers. Adults measure three inches (7.5 cm) in length and three-eighths inch (1 cm) in width. One subspecies has two irregular dark stripes down its back.

The sting of a nonlethal scorpion has been described as similar to that of a wasp or hornet, although usually somewhat more severe, and should be treated in an identical manner. (Scorpion venom is not identical to insect venom, and individuals allergic to insect stings usually are not allergic to scorpion stings.) Lethal scorpion stings are more painful, but fatalities have been limited almost entirely to small children.

Initially the sting of a scorpion of one of the lethal species produces only a pricking sensation and may not be noticed. Nothing can be seen at the site of the sting. (Swelling and red or purple discoloration are indications that the sting has been inflicted by a nonlethal species.) Pain follows in five to sixty minutes and may be quite severe. The sting site is quite sensitive to touch and is the last part of the body to recover. Tapping the site produces a painful tingling or burning sensation that travels up the extremity toward the body. (Apparently stings by other species of scorpions can occasionally produce a similar sensation.) Sensitivity may persist as long as ten days, although other symptoms usually disappear within ten hours.

Individuals who have been stung typically are extremely restless and jittery. Young children writhe, jerk, or flail about in a bizarre manner that suggests a convulsion. Their movements are completely involuntary. However, in spite of their constantly moving bodies, the children can talk. Although they appear to be writhing in pain, they usually state that they do not hurt. Convulsions have been described, but the true nature of these events is questionable. Visual disturbances such as roving eye movements or a fluttering type of movement known as nystagmus are common. Occasionally a child complains that he can not see, but nothing abnormal can be found when examining his eyes, and sight returns spontaneously in a few minutes. Children under six years of age may develop respiratory problems such as wheezing and stridor, and a few may need assisted respiration. Persons who have been stung typically have an elevated blood pressure, which may be an important diagnostic sign since hypertension is rare in children. The blood pressure usually returns to normal within four to six hours and becomes life-threatening only in infants.

Elderly individuals with preexisting health problems and small children stung by one of the lethal scorpion species should be taken to a hospital. Only a medical facility of that sophistication has the equipment and supplies necessary to monitor these individuals and deal with any complications that may arise. An ice cube applied to the site of the sting may help reduce pain, but no other therapy is possible outside a hospital. In locations such as the Grand Canyon, where prompt evacuation is not possible, diazepam can be given to children for control of the involuntary movements.

Other countries have species of lethal scorpions much more deadly than those in the Southwestern United States. Mexico reportedly has had as many as 76,000 scorpion stings resulting in 1,500 deaths in a single year. The stings of such scorpions must be treated with antivenin, which is rarely obtainable outside a hospital, particularly by someone who does not speak the country's language. Death from the stings of such scorpions is usually the result of sudden, very severe high blood pressure. Adrenergic blocking agents such as propranolol may be an effective method for treating such stings and probably should be carried by visitors to the countries where such lethal species of scorpions exist.