This is a non-contagious affection, called the Nettle Bash, from the reddish patches of swelling which mark the disease, resembling those produced by the sting of nettles. There is usually a state of feverish excitement in the system a day or two before the rash appears, which subsides on the appearance of the rash. Being attended with excessive itching, it causes the patient to rub or scratch the skin, and thus very much to increase the eruption, which will often,under this kind of irritation, extend itself far beyond its original boundaries. It may attack any part of the body, but is most common upon the inside of the forearms, and about the shoulders, loins and thighs; sometimes it makes its appearance first on the body, and sometimes, but not often, attacks the face. The eruption is not constant, but comes and goes irregularly, generally being worst at night. The swellings sometimes last only a few minutes, at other times for several hours, and on disappearing in one place, often return in another.

In many cases, the eruption makes its appearance without previous fever; especially when the disease proceeds from something taken into the stomach. In such cases, an hour or two after the substance has been swallowed, pain in the stomach, with nausea, anxiety, and headache come on, and are soon followed by the eruption, which is sometimes very violent. The face, neck, and chest, sometimes even the whole surface of the body, are much swollen, with considerable redness, interrupted here and there by single or clustered swellings. There is heat, itching, and tingling of the skin, and oppressed breathing, which sometimes almost threatens suffocation. This state usually only continues for a few hours, after which the complaint gradually subsides, and terminates usually in one or two days. In some cases there is only redness of the skin without the wheals. In these cases, the symptoms usually disappear very soon after the stomach has been completely evacuated by means of an emetic.

Occasionally acute Nettle Rash assumes a decidedly intermittent character, occurring in regular paroxysms every day, or every other day, either as an attendant on intermittent fever, or as an original affection.

In the chronic form there is no fever, and the eruption is not constant, but appears and disappears irregularly; being sometimes absent for a considerable period, and returning from slight causes, as violent exercise, or indulgence at the table. The wheals are usually whitish, and less apt than in the acute form to be surrounded by a red efflorescence, though attended with the stinging, itching, and tingling sensations characteristic of the disease. The duration of the complaint is very uncertain, sometimes not exceeding a few days, and sometimes lasting for months or years.

Occasionally the wheals increase rapidly, and attain a considerable magnitude, forming tumours in the loins, limbs, etc, sometimes as broad as the hand, and interfering with movement. These tumours are sometimes hot, tender and painful, occur usually at night, and subside after continuing a few hours, leaving behind them sensations as if the patient had been bruised or fatigued. In other cases, the wheals, instead of lasting only a few hours or a day, remain for two or three weeks after the redness has disappeared, retaining more or less of their characteristic sensation, and, at length, gradually subside. In one variety of the complaint, the patient suffers much from severe stinging pains as if needles were run into the skin, without any appearance of rash, except an occasional eruption of wheals, which continue for two or three days, and then disappear, without any relief to the unpleasant sensations.

The Nettle Rash, though a very disagreeable and often troublesome complaint, is scarcely ever dangerous. Cases of death have been recorded, when the disease has arisen from substances taken into the stomach; but, in these cases, the rash is only an outward symptom of the disturbance within.

The most frequent causes of the Nettle Rash are internal irritations, especially of the stomach and bowels. It often accompanies teething and the bowel complaints of children. Acids and other irritating matters in the stomach frequently occasion it. Certain kinds of food have been long known to produce it in particular constitutions; such as lobsters, crabs, shrimps, and more especially muscles. Salt and smoked fish have been accused by some writers; and it seems that fish are more poisonous at some seasons than at others, and that some parts of fish are worse than other parts. Pork, mushrooms, honey, oatmeal, bitter almonds, and green cucumbers have also been accused. One American author states the worst case of Nettle Rash he ever saw occurred in a woman from eating raspberries. He says, "She had been twice before attacked in the same manner, from the same cause. The face, neck, and extremities were greatly swollen, and the respiration in the highest degree embarrassed; but immediate relief was obtained by an emetic of Ipecacuanha." In this case probably the patient had partaken immoderately of the raspberries, or else she was peculiarly susceptible to their influence. (I once knew a lady who could not enter a room containing sweet peas without fainting. It was not necessary that she should see them; the smell was sufficient.) Certain medicines also occasionally produce it, among which are Valerian, Copaiba, and Turpentine. This susceptibility to particular kinds of food is not general, but confined to individuals; the food that will produce it in one person will not generally produce it in another, each person being liable to be affected by some special substance.

Over-exercise, strong mental excitement, indulgence in rich and high-seasoned food, and intemperance in drinks, sometimes produce attacks of Nettle Rash. So also will exposure to sudden changes of heat and cold. The disease attacks all ages; but it is most common in infants, and in young persons of the sanguine temperament, and women are more liable to it than men, probably because their skin is more delicate.

Treatment

In infants and young children the complaint may generally be got rid of by mild doses of Magnesia, or Magnesia and Rhubarb, repeated daily for two, three, or four days. When it is well known that any noxious substance has been taken into the stomach, a mild emetic of Ipecacuanha, administered before the laxative, will be beneficial. In grown persons, in chronic cases, particularly in those persons who are subject occasionally to returns of the complaint, I have found the most decided benefit from small doses of Bi-carbonate of Soda; say from five to ten grains, taken three times a day in a little water, or about a wine-glassful of Infusion of Cascarilla Bark. When persevered in sufnciently long, say for three or four weeks, I have not only never known it to fail, but I have known in some cases years to pass away without a return of the complaint. Warm bathing will sometimes be beneficial; and where the irritation and itching have been very distressing, I have known sponging the body with Morphia dissolved in warm water (about a grain of Morphia to four ounces of water) to give great relief. A little smarting will be felt at first, but that soon subsides, and a feeling of comfort is the result. But in order to cure the complaint, internal remedies are absolutely necessary.