Syphilis.—Careful examination should be sufficient to make a correct diagnosis. The papular, and other varieties, will usually give some distinct sign of the syphilitic contamination.
Urticaria.—The lesions of urticaria are mostly uniform and of a white color, usually of short duration (rather evanes cent) and are not likely to present differ ent stages.
Pemphigus. — The lesions of pern phigus are bullous, always remain so, and depart as such, while they appear rapidly and are asymmetrical; they are not ac companied with much inflammation.
Dermatitis Ilerpetiformis.—In this affection the lesions are multiform (ery thematous, vesicular, bullous, or pustu lar), are not symmetrical, and usually run a chronic course.
Erythema Nodesum.—The lesions are deep seated and nodular, are usually ob served upon the lower extremities (along the tibia), do not change in appearance, and are painful (almost rheumataform) at all times.
Erythema exudativum multiforme is a well-characterized and independent disease, to be distinguished from other erythemata produced by infectious dis ease. The disease is especially to be dis tinguished from erythema nodosum, and is quite independent of gout or rheuma tism. The morbid phenomena are in flammatory in nature, and are caused by the local irritative effects of certain in fective materials. Veiel (Practitioner, Nov., '96).
ETIOLOGY.—The cause or causes of this affection are obscure. It presents a tendency to recur at certain seasons of the year (usually the spring and fall), and is probably influenced by climatic changes.
Erythema multiforme regarded as a catarrhal disease. By this is meant that the same causes which produced catarrhs in people with susceptible mucous mem branes produced this eruption in those with susceptible skins. Hutchinson (Clinical Jour., Nov. 6, '95).
Numerous cases are recorded in which the affection recurred at regular inter vals, as, for instance, every year at the same time, every three months, at inter vals of six or more months, or at longer stated intervals. All ages are affected, and the disease seems to more greatly at tack young children and young females.
There is no doubt but that certain affec tions predispose to its appearance; thus rheumatism, gout, uracmia, Bright's dis ease, jaundice, diphtheria, and cholera.
Cases of erythema multiforme de scribed where, owing to faulty processes in the digestive tract, the production and absorption of toxins were possible. Examination of the urine and faeces dis closed a large excess of indol, skatol, indoxyl, and skatoxyl, as well as phenols and organic compounds of sulphuric acid. Disinfection by calomel was followed by very rapid cure. E. Freund (Amer. Medieo-Surg. Bull., Apr. 25, '94).
Under the designation toxic erythema attention called to a form of erythema occurring in the course of pus-formation. It is most commonly encountered in young children. Its form is usually macular or punctate, though occasion ally of the papular of vesicular variety, and its course mild and of short dura tion, accompanied by moderate rigors, with rise of temperature, and subse quent desquamation.
The common form of small discrete macules of faint pink color, appearing first upon the abdomen and sides of the chest, few in number and widely dis tributed, are seen in the milder forms of endocarditis and empyema, tubercular abscesses, etc. In some cases of abscess of the middle car or the mastoid this form is seen; but usually attendant upon these conditions we find the mac ular eruption rapidly changing to a Popular, and in the severer cases to a vesicular form, with rigors of moderate severity, headache and backache at the beginning, followed by rise of tempera ture. These symptoms may follow an infected wound, accidental or intentional (as in vaccination), where there is rapid formation of pus and absorption of the toxic products of the same. The ery thema is only a part of the general proc ess, representing the action of toxins on the vasomotor centre. Cuthbert R. Bar ham (Med. News, Mar. 28, '96).
Certain drugs taken internally may alike be mentioned as a possible influ ence.