Either acute erythema or urticaria may be caused in some persons by eating fish, and particularly shellfish and crustaceans, as oysters, clams, lobsters, shrimps, and crabs. It is also produced by strawberries, bananas, and other forms of fruit. Crustaceans and strawberries are perhaps the most common excitants.

The action of the food poison is wholly different from that of ptomaines (p. 379), for it originates from fresh as well as stale food, and may be derived, as in the case of strawberries, from.vegetable food. Some persons have an attack regularly every spring when strawberries first appear on the table. Others show occasional immunity, depending upon their condition at the time. Those persons who are hurt by one kind of poisonous food are not necessarily affected by the others. The whole matter seems to be influenced solely by idiosyncrasy.

Other alimentary substances which have been observed to sometimes poison are pork in various forms, sausages, mushrooms, cheese, and even mutton (Jackson).

Symptoms

The eruption develops suddenly and within from two to six hours after ingestion of the food. It is commonly a typical urticaria with large pink wheals, which quickly come and go over all parts of the body. They are accompanied by intense itching and burning. This affection usually lasts but a few hours, or possibly for two or three days, though sometimes it may continue for several weeks.

Treatment

The eruption usually disappears upon withdrawing the offending article from the diet, and giving a saline cathartic and some simple remedy to regulate digestion and prevent fermentation, such as salol, salicin, or rhubarb and soda. Large quantities of water should be drunk.

The troublesome itching is best relieved by sponging with common baking soda, a teaspoonful to a quart of water, or a solution may be applied to the wheals of menthol and chloral, each a drachm, in a couple of ounces of a mixture of equal parts of alcohol and camphor water. A 1-40 carbolic-acid solution may be similarly applied.