490 DISEASES OF THE SKIN. 



succession. In the severer form (lichen agrius) , the outbreak is some- 

 times accompanied by fever, and by general disturbance. The nodules 

 are often crowded closely together, and stand upon a reddened base. 

 They are likewise red themselves, and itch and burn intensely. The 

 Inflammation readily becomes aggravated, so that in a few days the 

 lichen changes into an eczema rubrum. The course of this variety may 

 also be acute, and terminate in recovery at the end of a week or fort- 

 night ; more usually, however, it becomes chronic. 



Hebra who never applies the term lichen to a papular eruption 

 unless the papules retain their solid form from beginning to end of 

 their course, and do not transform into vesicles or pustules describes 

 lichen ruler as a disease which, in its later stages, bears some resem- 

 blance to psoriasis. Here there are red nodules of the size of a millet- 

 seed, which are covered with thin scales, and which at first are separate, 

 and do not itch nor extend at the periphery. With every succeeding 

 outbreak of the eruption, the part becomes more thickly studded with 

 nodules, and the intervening surface grows smaller, until at last the 

 edges of the papules touch one another, and form large, infiltrated, red 

 patches. Finally, the entire cutaneous surface may become the seat 

 of such a papular eruption, and of the diffuse infiltration arising from 

 it. Like all other universal exanthemata, this has a prejudicial effect 

 upon the general health of the patients, the majority of whom die in a 

 state of marasmus. 



TREATMENT. The slighter forms of acute lichen require no treat- 

 ment. In especially obstinate cases we may have recourse to the 

 exhibition of arsenic. Veiel believes this to be of most service in all 

 those cutaneous diseases in which the cutis is infiltrated, while in other 

 forms it is much less efficient. Cold applications and the exhibition 

 of laxatives are the suitable remedies for lichen agrius ; but blood-let- 

 ting, which likewise has been recommended, should never be practised. 

 Chronic lichen agrius often defies the most active treatment. Baths, 

 soft soap, tar, and the preparations of sulphur, but especially the inter- 

 nal administration of arsenic, are the remedies most to be advised. 



CHAPTER XIV. 



PRURIGO DERMATITIS WITH SMALL, SCATTERED, ITCHING NODULES. 



ETIOLOGY. The flat nodules which are peculiar to prurigo have 

 the color of the surrounding skin. If punctured, they usually dis- 

 charge a drop of clear liquid, while the puncture of a papule of lichen 

 is followed by the flow of a drop of blood. Upon squeezing a prurigc 

 nodule laterally, we observe that the epidermis becomes stretched 



