To make certain that a poisonous snake has caused the bite, first
examine the wound for teeth marks. In a perfect bite by a poisonous
snake (excluding the coral snake), the pattern will reveal two
distinctly larger holes where the fangs have entered the flesh. There
also may be two rows of smaller teeth marks between these punctures.
[Illustration: Snakebite patterns]
Furthermore, if the snake engages the lower jaw, two additional rows of
small teeth impressions will be seen below the first group.
Frequently the bite pattern is not a clear one. For example, if the
snake pulls to one side as it disengages the fangs after a strike, the
result is a series of scratch marks instead of punctures. There is also
the possibility that the snake will engage only a single fang; or,
perhaps, during fang replacement, two fangs are temporarily in position
on one or both sides of the upper jaw. Any of these conditions, as well
as others, can contribute to an obscure bite pattern.
The bite of a coral snake often is difficult to diagnose by examination
of the wound. Because this snake impels its fangs in a sort of chewing
motion, the pattern created by its bite may be two groups of closely
spaced punctures where the fangs have entered the flesh a number of
different times.
A clearly defined harmless snake bite pattern consists of a series of
uniformly small punctures (four rows made by teeth in the upper jaw, two
rows by teeth in the lower), but always without the large fang holes.
More typically, a non-poisonous bite produces several rows of scratches.
Pit-viper poisoning is diagnosed primarily by the presence of _local_
signs and symptoms. The most important of these are:
1. _Pain_ accompanies most poisonous snake bites. Generally intense
and burning in character, it becomes more severe with the passing of
time. This symptom alone is not conclusive because pain can be
imagined following a non-poisonous bite. Occasionally in a severe
bite, the pain is replaced by numbness and tingling.
2. _Swelling_ at the bite area is present in every case of poisoning.
It will appear within five to 30 minutes. In a severe case, the
swelling may continue to spread for 24 hours. There will be no
swelling from a bite by a non-poisonous snake or by a poisonous snake
that injected no venom.
[Illustration: Snakebite swelling]
3. _Discoloration_, reddish or bruise-like in appearance, begins around
the fang punctures within a half hour and becomes gradually more
extensive.
Intense local pain is symptomatic of coral snake poisoning but, unlike a
case of pit-viper poisoning, swelling and discoloration are not
pronounced. Diagnosis of coral snake envenomation is difficult and must
be based primarily on systemic symptoms: headaches, weakness, lethargy
and facial paralysis.