Pathologically, the wheals of urticaria are produced by a sudden edema and exudation in a limited area of the upper layers of the skin, probably due to spasmodic contraction of the capillaries from vasomotor influence. The resistance of the tissues of the skin to the semisolid swelling being the greatest at the center, and reddish border. Most observers agree that urticaria is an angioneurosis similar to erythema multiforme, but a few consider that the lesions are caused by the action of irritation upon the blood-vessel walls.

Diagnosis. The patches of erythema simplex are larger, have not developed from wheals, and are not elevated above the surface. In erythema multiforme, the lesions are much more persistent, and are unattended with marked subjective sensations. Moreover, they are apt to by symmetrical, and in erythema nodosum tender to pressure. Pemphigus might be mistaken for urticaria bullosa, but the latter will show one or more wheals and a brief duration. Erysipelas presents more diffuse swelling and redness, is of longer duration, and has marked constitutional symptoms. Insect bites can usually be distinguished by the minute puncture in the center of the lesion, although it is well to remember that a more or less general urticaria may follow a single insect wound.

Prognosis. It is most favourable for the average case if preventive and curative measures are observed, but a chronic attack may exhaust the entire therapeutic domain, largely because the causal factors are not always easily discovered.

Treatment. Causal treatment is most important. If the cause is evident, it is easily removed; but, if hidden, a thorough examination of the history and the present condition of the patient, including the various excretions, should be insisted upon. If it be due to a general or localized disease, a continuous, persistent physiological treatment may be necessary. Disorders of the kidneys, uterus, nervous system, respiratory tract, and especially the alimentary tract, or conditions due to pregnancy, dentition, or the menopause, general diseases like malaria, gout and rheumatism, may furnish indications for treatment. If acute urticaria be due to irritating contents of the stomach, an emetic such as 20 drops of ipecac may be given to cause vomiting, or, in some few case, if the irritation is intestinal, an effective cathartic, such as castor oil or saline water, may be given to remove the causal factor. In many instances a culture of the bacillus Bulgaricus may be used to relieve intestinal fermentation, but in all cases the internal remedy should be given, because it not only hastens the immediate relief, but tends to prevent a recurrence, and may be as effective in relieving the subjective sensations as any form of local treatment. The latter, however, is essential because immediate relief from the intolerable itching is demanded and cannot be ignored. It is often sufficient to employ the alkaline baths containing sodium bicarbonate, sodium biborate, potassium bicarbonate, or sodium hyposulphite. Starch, gelatin or bran may be added to these baths or used alone. Carbolic acid, tar, menthol, camphor, thymol and chloral may be used in varying strength, or the calamin-zinc-oxid lotion, liquor carbonis detergens (1 to 3 ounces to a pint of water) or one of the following formulas:

R Menthol., gr. xxx; 2

Phenol., 3j; 4

Aq.hamamelidis, 3j; 30

Zinci odixi, 3ij; 8

Glycerini, 3ij; 8

Spirit. vini rect, 3ij; 60

Aquae camphorae 3ij; 60 M

Aquae, q.s.ad 3viij; 240

R Phenolis, 3ss; 2

Glycerini, 3ss; 2

Alcoholis, 3j; 30 M

Aquae, q.s.ad 3viij; 240

R Thymolis gr.xv; 1

Glycerini, 3ij; 8

Frederick Dearborn
Dr Frederick Myers DEARBORN (1876-1960)
American homeopath, he directed several hospitals in New York.
Professor of dermatology.
Served as Lieut. Colonel during the 1st World War.
See his book online: American homeopathy in the world war