#What is the course of dermatitis herpetiformis?# Extremely chronic, in most instances lasting, with remissions, indefinitely. The skin is rarely entirely free. From time to time the type of the disease may undergo change. From the continued irritation and scratching more or less pigmentation results. #What is to be said in regard to the etiology?# The disease is in many instances essentially neurotic, and in exceptional instances septicaemic. Pregnancy and the parturient state are factors in some instances (so-called herpes gestationis). It is possible in some instances that the eruption may be an expression of a mild toxemia of gastro-intestinal origin. In some cases no cause can be assigned. In the majority of patients the general health, considering the violence of the eruptive phenomena, remains comparatively undisturbed. Nervous shock and mental worry are factors in some cases. Polyuria, with sugar in the urine, has occasionally been noted. Eosinophile cells have been found both in the vesicles and the blood. In some instances--exceptionally, it is true--the disease has appeared shortly after vaccination. #Mention the diagnostic features of dermatitis herpetiformis.# The multiformity of the eruption, the characters of the lesions, the disposition to grouping, the absence of tendency to form solid sheets of eruption (as in eczema), the intense itching, history, chronicity and course. In doubtful cases, an observation of several weeks will always suffice to distinguish it from eczema, erythema multiforme, herpes iris and pemphigus, diseases to which it at times bears strong resemblance. #Give the prognosis of dermatitis herpetiformis.# An opinion as to the outcome of the disease should be guarded. It is exceedingly rebellious to treatment, and relapses are the rule. Exceptionally the bullous and pustular varieties prove eventually fatal. The erythematous and vesicular varieties are the most favorable. #State the treatment to be advised.# There are no special remedies. Constitutional treatment must be conducted upon general principles. A free action of the bowels is to be maintained. In occasional instances arsenic in progressive doses seems of value. Externally protective and antipruritic applications, such as are employed in the treatment of eczema and pemphigus, are to be employed:-- [Rx] Ac. carbolici, ....................... [dram]j-[dram]ij Thymol, .............................. gr. xvj. Glycerinae, ........................... [Oz]ss-[Oz]j Alcoholis, ........................... f[Oz]ij Aquae, q.s., ......... ad ............. Oj. M.