The little red spots of irritation or itching which forms at the mouths of the sweat glands were supposed to be due to the irritation of the perspiration on the sensitive skin, but we recently have had a somewhat different explanation of the cause.
The question is, why the perspiration should be irritating in hot weather, and not so irritating when it occurs in a heated house in the winter, or on a warm day in spring or fall. Of course, it might be said that the perspiration is excessive in summer, and macerates the skin and makes it more delicate and, hence, more susceptible to this form of irritation.
Another feature of the condition, which was not explained on the basis above mentioned, was the predilection of prickly heat for certain skin areas, as under the arms, under folds of skin, and under the breasts in fat people, etc.
I mentioned in another placebut it will bear repeatingthat this has attracted the attention of a physician, who found that perspiration normally contains a small amount of sugar, and that the perspiration from the places mentioned has rather a higher percentage of sugar than any place else. Perspiration of this character is a good culture medium for sugar-loving yeast organisms, and it is the growth of these which produces the irritation of the skin. Inasmuch as they are more likely to be on hand in the summer than in the winter, this explains the fact that prickly heat occurs more often in warm weather.
Medical advice on the treatment of prickly heat always has emphasized the fact that a mild antiseptic, such as boric acid, salicylic acid, or alcohol, will help this condition. Nobody knew the explanation, but if the theory I have just outlined is true, the explanation is at hand, because the antiseptic solutions keep off the sugar-loving yeast organisms.
Perhaps even better than any of the dusting powders or lotions that have been used for the condition is phenylmercuric nitrate ointment, which was mentioned as a remedy for ringworm infection.