492 DISEASES OF THE SKIN. 



waist-band, while the favorite harbor of the itch-insect is upon the 

 flexor sides of the limbs, between the fingers, and upon the belly, where 

 the prurigo-papules do not often come. However, the positive dis- 

 covery of the tracks of the itch-insect, or the detection of the insect 

 itself, or the presence of lice, or their nits, furnishes a criterion for dis- 

 tinguishing between scabies, prurigo pedicularis, and true prurigo, bet- 

 ter even than that afforded by the seat of the papules and excoria- 

 tions. But even in the face of such testimony as this, when the itching 

 is of very long standing, and involves an unusually large extent of sur- 

 face, we should bear in mind the possibility of a complication of these 

 diseases, the more so since persons of the class most liable to prurigo 

 are equally likely to be infested by lice and the itch-insect. The dark 

 stain, seen upon the skin of patients who have long suffered from pru- 

 rigo, is a consequence of the scratching, and is of no service as a diag- 

 nostic mark, since it is nearly always seen upon the skin of people 

 who have long been infested by vermin. Slighter grades of prurigo 

 are called prurigo mitis / the severer grades are called prurigo formi- 

 cans, from the resemblance of the sensations to the intolerable itching 

 and burning produced by the contact of a multitude of ants. Prurigo 

 ani, which is limited to the region of the anus, and that form which 

 appears upon the labia majora in women, and upon the penis and 

 scrotum in men or prurigo pudendorum is intermediate between 

 prurigo and eczema. As has already been stated, this is a most ob- 

 stinate affection, and may last with undiminished intensity for months, 

 and even for years. Generally, however, it grows worse during the 

 autumn and winter, and makes a remission during the spring and sum- 

 mer. The itching is usually most distressing in the evening, and at 

 night. So constant are the disquiet and torment of the patients, who 

 are often deprived of their sleep night after night, that, driven to des- 

 peration, they sometimes commit suicide, while others become insane. 

 On the other hand, the general state of the nutrition does not often 

 suffer ; at all events, not until very late in the disease. Any prema- 

 ture marasmus which may exist is much more frequently dependent 

 upon complications, or upon the needy circumstances of the patient 

 (cachexia pauperum^, tnan upon the prurigo itself. 



TREATMENT. The radical cure of prurigo is a task so difficult 

 that it is rarely accomplished. On the other hand, it is nearly always 

 possible to produce a temporary abatement of the symptoms, and 

 sometimes, indeed, to effect a complete although transient relief, by 

 stimulating the process of desquamation of the cuticle by means of 

 cutaneous irritants, thus accelerating the process of its regeneration. 

 Hence, baths or lotions containing a solution of common salt, potash, 

 3orrosive sublimate, lime-water, or dilute acid, inunctions of tar-oint- 



