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 seborrhœa (eczema seborrhoicum), as being of a vegetable-parasitic origin, and as a mildly inflammatory affection somewhat similar to psoriasis. It is not a frequent disease.