Definition. An inflammatory condition of the skin caused by contact with deleterious vegetable or mineral substances.
Symptoms. All degrees of inflammation may be experienced in this disease due to a number of influences enumerated under etiology. The eruption may be present in the form of macules (erythema0, papules, vesicles, wheals, blebs, pustules and edematous swelling. In rare cases, superficial ulceration or even gangrene may be experienced. The ordinary type, however, r runs an acute course and recovers spontaneously. Burning and itching are usually present in a variable degree but may be hardly noticeable or absent. It is unnecessary to recite the varieties of this condition caused by host of agents because they must be specified to some extent under etiology.
However, the eruption due to exposure to the rhus plants (rhus poisoning, ivy poisoning) especially rhus toxicodendron (poison ivy and poison oak) are so prevalent in America that it is necessary to briefly consider their symptoms and differential points. Numerous closely studded vesicles and blebs develop on a red and swollen surface accompanied by marked burning and itching, a few hours to several days after exposure. The hands, feet, anal and genital regions are the typical locations, but the eruption may be carried to various parts of the body by autoinoculation. The condition lasts from one to four weeks. While most individuals enjoy comparative immunity, some are so susceptible that being in the proximity of the plant, without actual contact, suffices to bring on an attack. Many persons become less susceptible as they grow older, while others enjoy spells of immunity. The condition may simulate erysipelas when the eyelids and other parts of the face are greatly swollen but there is an absence of high fever and other systemic disturbances of that disease. Acute eczema does not give the typical history or rapid evolution of poison ivy dermatitis.
Etiology. those substances that might cause dramatic inflammation are well nigh innumerable and their action is for the most part chemical. No doubt the susceptibility of the individual, the exact nature of the irritant, and the length of contact, as well as such underlying conditions as the catarrhal, gouty, rheumatic and neurotic diatheses act as predisposing factors. Among the active causative agents may be mentioned arnica, mustard, capsicum, cantharides, mercury, Croton oil, chrysarobin, turpentine, iodoform, iodin, alkalies, acid, dye stuffs and petroleum products. There are also nearly seventy of our native plants which possess irritating properties, such as the nettle, primrose, cowhage, nasturtium, smartweed, podophyllum, balm of Gilead, oleander, ruta and especially the plants of the rhus species (toxicodendron, venenata, diversiloba and vernix). The poisonous principle in ordinary rhus poisoning is toxicodendric acid, and in severe cases it is probably absorbed into the system and eruptions results therefrom on distant portions of the skin. The drug taken internally will cause similar symptoms. Contact with external substances incident to many occupations is the cause of frequent eruptions. Most of the so-called trade eruptions become eczematous and are properly considered under that head, but being due to external causes they might be considered, in their early development, as forms of dermatitis venenata. For instance, bakers, grocers, stonecutters, bricklayers, dyers and washerwomen may develop such an eruption. A similar condition exists among professional people, such as dentists, surgeons and physicians (professional dermatitis). Probably mercuric chlorid, formalin, lysol and carbolic acid are mainly responsible for these eruptions.
Prognosis and Treatment. The removal of the cause usually terminates the various forms of dermatitis referred to. Local treatment is the same as for acute eczema, plus the removal of the cause and future avoidance of it. Poison ivy is so exclusively an American disease that its treatment should be well understood. In mild cases, wet dressings of saturated solutions of sodium hyposulphite or boric acid, 10 to 25 per cent. of succus calendula, 2 to 4 per cent. potassium permanganate, or 1 part of electrozone to 2 parts of distilled water may be used. If the case are more severe, it is wise to open the vesicles and blebs before applying the dressing: then carron oil, some bland oil, or 50 per cent. aqueous solution of ichthyol, or 1 to 5 per cent. creolin in glycerin may be used. If the area involved is small, collodion may be applied or a 25 per cent. solution of adrenalin chlorid (1:000) in collodion is even better. Internal remedies have their virtue in many of these cases especially in those due to rhus poisoning. See indications for Apis, Arnica, Cantharis, Graphites, Hepar sulp., Rhus tox., Rhus ven. and Sulphur.