_[beta]-Naphthol_ and _resorcin_ are applied as ointments, thirty to sixty grains to the ounce, and as they are (especially the former) practically free from staining, may be used for exposed surfaces.

Gallacetophenone and aristol also act well in some cases, applied in five- to ten-per-cent. strength, as ointments.

In obstinate patches the _x_-ray may be resorted to, employing it with caution and in the same manner as in other diseases.

Pityriasis Rosea.

(_Synonym:_ Pityriasis Maculata et Circinata.)

What do you understand by pityriasis rosea?

Pityriasis rosea is a disease of a mildly inflammatory nature, characterized by discrete, and later frequently confluent, variously sized, slightly raised scaly macules of a pinkish to rosy-red, often salmon-tinged, color.

Upon what part of the body is the eruption usually found?

The trunk is the chief seat of the eruption, although not infrequently it is more or less general.

Describe the symptoms of pityriasis rosea.

The lesions, which appear rapidly or slowly, are but slightly elevated, somewhat scaly, usually rounded, except when several coalesce, when an irregularly outlined patch results. At first they are pale or bright pink or reddish, later a salmon tint (which is often characteristic) is noticed. The scaliness is bran-like or flaky, of a dirty gray color, and, as a rule, less marked in the central portion; it is never abundant. The skin is rarely thickened, the process being usually exceedingly superficial.

What course does pityriasis rosea pursue?

The eruption makes its appearance, as a rule, somewhat rapidly, usually attaining its full development in the course of one or two weeks, and then begins gradually to decline, the whole process occupying one or two months.

To what is pityriasis rosea to be attributed?

The cause is not known; it is variously considered as allied to seborrh[oe]a (eczema seborrhoic.u.m), as being of a vegetable-parasitic origin, and as a mildly inflammatory affection somewhat similar to psoriasis. It is not a frequent disease.

How is pityriasis rosea distinguished from ringworm, psoriasis and the squamous syphiloderm?

From ringworm, by its rapid appearance, its distribution, the number of patches, and, if necessary, by microscopic examination of the sc.r.a.pings.

Psoriasis is a more inflammatory disease, is seen usually more abundantly upon the limbs, the scales are profuse and silvery, and the underlying skin is red and has a glazed look; moreover, psoriasis, as a rule, appears slowly and runs a chronic course.

The squamous syphiloderm differs in its history, distribution, and above all, by the presence of concomitant symptoms of syphilis, such as glandular enlargement, sore throat, mucous patches, rheumatic pains, and falling out of the hair.

State the prognosis of pityriasis rosea.

It is favorable, the disease tending to spontaneous disappearance, usually in the course of several weeks or one or two months.

What treatment is to be advised in pityriasis rosea?

Laxatives and intestinal antiseptics, and ointments of salicylic acid (5-15 grains to the ounce), of sulphur (10-40 grains to the ounce); or a compound ointment containing both these ingredients can be prescribed.

The ointment base can be equal parts of white vaselin and cold cream; in some instances La.s.sar's paste (starch powder, zinc oxid powder, each, [dram]ij; vaselin, [dram]iv) seems more satisfactory.

Dermat.i.tis Exfoliativa.

(_Synonyms:_ General Exfoliative Dermat.i.tis; Recurrent Exfoliative Dermat.i.tis; Desquamative Scarlatiniform Erythema; Acute General Dermat.i.tis; Recurrent Exfoliative Erythema; Pityriasis Rubra.)

Describe dermat.i.tis exfoliativa.

Dermat.i.tis exfoliativa is an inflammatory disease of an acute type, characterized by a more or less general erythematous inflammation, in exceptional instances vesicular or bullous, with epidermic desquamation or exfoliation accompanying or following its development. Const.i.tutional disturbance, which may be of a serious character, is sometimes present.

It is a rare and obscure affection, running its course usually in several weeks or months, but exhibiting a decided tendency to relapse and recurrence. In many cases it is persistently chronic, with exacerbations and remissions. In some instances it develops from a long-continued and more or less generalized eczema or psoriasis, and in exceptional cases it is started by the careless use of mercurial ointment and of chrysarobin ointment.

[Ill.u.s.tration: Fig. 19. Dermat.i.tis Exfoliativa.]

In another type of the disease, formerly described as _pityriasis rubra_, the skin is pale red or violaceous-red, but is rarely thickened, continued exfoliation in the form of thin plates taking place. Its course is variable, lasting for years, with remissions.

An exfoliating generalized dermat.i.tis is exceptionally observed in the first weeks of life (_dermat.i.tis exfoliativa neonatorum_), lasting some weeks, and in most cases followed by recovery. There are no special const.i.tutional symptoms, the fatal cases usually dying of marasmus.

As will be seen dermat.i.tis exfoliativa varies considerably in degree; it may be extremely mild, resembling in appearance the scarlet-fever eruption (erythema scarlatiniforme) and running a rapid course; or the skin-condition and the systemic symptoms may be of grave and persistent character.

Give the treatment of dermat.i.tis exfoliativa.

General treatment is based upon indications, and externally soothing applications, such as are employed in acute and subacute eczema, are to be used.

Lichen Pla.n.u.s.

What is lichen pla.n.u.s?

Lichen pla.n.u.s is an inflammatory disease characterized by small, flat and angular, smooth and shining, or scaly, discrete or confluent, red or violaceous-red papules, having a distinctly papular or papulo-squamous course, and attended with more or less itching.

Describe the symptoms of lichen pla.n.u.s.

The eruption, as a rule, begins slowly, usually showing itself upon the extremities; the forearms, wrists and legs being favorite localities. It may appear as one or more groups or in the form of short or long bands.

Occasionally its evolution is rapid and a considerable part of the surface may be invaded. The lesions are pin-head to small pea-sized, irregularly grouped or so closely crowded together as to form solid patches; they are quadrangular or polygonal in shape, usually flat, with central depression or umbilication, and are reddish or violaceous in color. At first they have a glazed or shining appearance; later, becoming slightly scaly, the scaliness being more marked where solid patches have resulted. New papules may appear from time to time, the older lesions disappearing and leaving persistent reddish or brownish pigmentation. Exceptionally the eruption presents in bands or lines, like rows of beads (_lichen moniliformis_). Very exceptionally a vesicular or bleb tendency in some of the lesions has been noted; doubtless, in most instances at least, this has been due to the a.r.s.enic so generally administered in this disease. In rare instances lichen pla.n.u.s lesions are also seen on the glans p.e.n.i.s and on the buccal mucous membrane. In some cases, especially in the region of the ankle, the papules become quite large (_lichen pla.n.u.s hypertrophicus_), and in occasional cases there is a tendency in some of the lesions or patches to clear up centrally. There is, as a rule, considerable itching. There are no const.i.tutional symptoms.

What is the etiology of lichen pla.n.u.s?

In some cases the disease is distinctly neurotic in character, in others no cause can be a.s.signed. It is more especially met with at middle age, and among the wealthier, professional, and luxurious cla.s.ses.