Pathology. — The development of a wheal is a process determined by a reflex mechanism set in motion by two sets of stimuli. Here, as elsewhere, the mechan ism must consist of afferent nerves, a centre, and afferent nerves, the centre being located in the plexus of fine fibres ramified through the superficial layers of the corium. The stimuli which awaken the activity of this system are direct or indirect; they are external irritants ap plied directly to the surface of the skin, —e.g., changes of temperature, nettles,— or they arise from the ingestion of certain substances endowed with toxic properties (Stephen Mackenzie). The wheal is a circumscribed swelling of the skin, at tended with engorgement of the vascular supply and an exudation of scrum into the cellular tissue around the vessels. The proximity to the absorbent vessels accounts for the early disappearance of the In the papilla,. form the papules are ascribed to urticarial exuda tion into the cuticular structures. Unna attributes the wheal to spasm of the ven ides whose functions are to carry off the lymph.
Treatment.—Urticaria being purely a symptomatic disorder, treatment shoUld aim to correct the primary etiological factor. But a few of these have been enumerated even in the long list given under ETIOLOGY: a statement emphasiz ing the need of careful inquiry into each case. The environments of the patient, his underwear, should be submitted to close scrutiny; the state of his digestive, reproductive, and urinary organs should be inquired into; and the class and quality of his food investigated. Dia thetic disorders—such as rheumatism and gout—demand special attention. As to the internal measures indicated for the eruption, atropine is considered valuable by Besnier; strophanthus hispidus by Rifat, who gives 10 to 20 drops daily: while iodide of potassium, arsenic, and quinine have also given excellent results in some cases.
The following mixture is highly recom mended as a local application for urti 13, Alcohol, Chloroform, of each, 3 parts. Sulphuric ether, Menthol, of each, 1 part.
M. To be applied in the form of spray. Gaudier (N. Y. Med. Jour., Apr.
9, '9S).
The following simple lotion is of great value in allaying the burning and itch ing of urticaria:— hnmainclis-water, 2 ounce.
Salt, 7, ounce.
Enough distilled water to make 1 pint.
To he applied freely. Skinner (Brit. Jour. of Dem.; Phila. Med. Jour.. Mar.
10, 1900).
(Jrticaria, produced by toxic foods, shell-fish, etc., is best met by lavage of the stomach or an emetic. A cup of lukewarm water is often sufficient for the latter purpose. A saline purgative should follow. In neurotic and arthritic cases sodium bicarbonate is often effi cacious, especially, according to Cerilly, if given per rectum. The injection should contain, for an adult, 5 drachms of the bicarbonate of sodium, 30 drops of the wine of opium, and 1 pint of boiled water. These are repeated sev eral times a day.
B. Wolff (Amer. Medico-Surg. Bull., May 25, 'OS) relieves the most acute ' symptoms of urticaria within a few hours, and effects a cure within twenty-four hours, by giving sodium phosphate in doses of 4 to 5 grains every three hours, in concentrated solution.
The following solution may be used topically:— Prepared calamin, 45 grains. Zinc oxide, 45 grains.
Carbolic acid, 15 grains. Lime-water, 1 ounce.
Rose-water, 2 ounces.—M.
Bulkley (Med. Rev. of Rev., June 25, 'OS) recommends the following applica tion as a calmative:— 13 Chloral, Camphor, of each, 1 drachm. Pulv. starch, ounce.
M. Sig.: Keep tightly corked in a wide-mouthed bottle. Rub in with the hand.
Fresh cocoanut-oil rubbed into the skin is of value. The fear of the oil spoiling one's clothes is groundless. The skin absorbs the oil; after two or three minutes' gentle rubbing the oil disap pears, and one can rub himself with a towel without any coming off, unless, of course, a great excess has been applied; then the towel will remove the excess.
The best time to put it on is before going out for the evening's exercise. One should strip, pour a little of the oil into the palm of the hand, and rub it over the body from the neck to the ankles. It is not advisable to use sponge or rag.
When coming in to dress for dinner, the bath is taken, no soap being used. There is no reason why the oil should not be used twice a (lay, if necessary, about a tablespoonful each time.
By adopting these simple means, many in liarrackpore have been saved from the inflictions of prickly beat during the hot seasons. II. R. II. Moore (Indian Med. Record, June 12, 1901).