HERPES. 



463 



arises upon other parts of the external genitals, might more properly 

 be called herpes pudendalis. Finally, there is herpes zoster or zona 

 (shingles), which extends, in a very peculiar manner, along the course 

 of the cutaneous nerves. When herpes zoster appears upon the 

 thorax, the groups of vesicles form a somewhat broad, interrupted belt, 

 which begins at one of the vertebrae, and, following the line of one of 

 the intercostal spaces, reaches to the sternum, but scarcely ever occurs 

 upon both sides of the body. When the eruption is upon the belly, 

 the groups of vesicles are arranged much as they are in zoster of the 

 chest, and extend from the lumbar vertebrae to the linea alba and 

 mons veneris. Upon the neck the vesicles sometimes form a half-collar, 

 sometimes they extend downward toward the second rib. Upon the 

 face, the eruption spreads along the course of the facial nerve, espe- 

 cially along the cheek, to the dorsum of the nose. Upon the scalp it 

 runs over the forehead and skull along the course of the supraorbital 

 nerve, or else spreads over the occiput along the course of the occipital 

 nerve. Finally, in zoster of the arm and thigh, the eruption of vesicles 

 follows the courses of the nerves which spring from the brachial and 

 crural plexus. All forms of herpes begin with a sense of burning pain, 

 usually not of a very severe character, in the affected region. Numerous 

 red points soon become visible, which coalesce, forming red specks of 

 irregular shape, which, on the next day, usually are covered with small 

 transparent vesicles. The contents of the vesicles, which rarely exceed 

 the size of a lentil or a split pea, become turbid in two or three days, 

 or else reddened from admixture of blood. About the third or fourth 

 day the vesicles commence to shrivel, and they and their contents sub- 

 sequently dry up into a brownish scab. The scabs fall off in from ten 

 days to a fortnight after the first appearance of the eruption, and for 

 some time afterward there remains a reddish spot, covered with thin 

 epidermis. The pain, which is of a burning character, though not very 

 severe t usually abates when the vesicles begin to shrivel. Herpes 

 zoster is sometimes accompanied by fever, and in rare instances the 

 eruption of vesicles is preceded by febrile disturbance, like the inflam- 

 matory cutaneous exudation of erysipelas. There is no fever in the 

 other varieties of herpes, or the fever, if present, does not depend upon 

 the herpes, but upon the disease with which the herpes is associated. 



Besides the forms of herpes above enumerated, there is also a 

 herpes circinatus and a herpes iris. These species are not classified 

 according to their locality, like the other forms, but according to the 

 arrangement of the vesicles. This is quite analogous to that of the 

 nodules in erythema circinatum and erythema iris. In herpes circina- 

 tus, a circle of vesicles encloses a tract of healthy skin. Moreover, the 

 vesicles themselves are usually smaller than those of other kinds of 



