Читать книгу Essentials of Diseases of the Skin - Henry Weightman Stelwagon - Страница 28
Comedo.
Оглавление(Synonyms: Blackheads; Flesh-worms.)
What is comedo?
Comedo is a disorder of the sebaceous glands, characterized by yellowish or blackish pin-point or pin-head-sized puncta or elevations corresponding to the gland-orifices.
At what age and upon what parts are comedones found?
Usually between fifteen and thirty, and upon the face and upper part of the trunk, where they may exist sparsely or in great numbers. They are occasionally associated with oily seborrhœa, the parts presenting a greasy or soiled appearance.
Exceptionally they occur as distinct, and usually symmetrical, groups upon the forehead or the cheeks. On the upper trunk so-called double and multiple comedo have been noted—the two, three, or even four closely-contiguous blackheads are, beneath the surface, intercommunicable, the dividing duct-walls having apparently disappeared by fusion.
Describe an individual lesion.
It is pin-point to pin-head in size, dark yellowish, and usually with a central blackish point (hence the name blackheads). There is scarcely perceptible elevation, unless the amount of retained secretion is excessive. Upon pressure this may be ejected, the small, rounded orifice through which it is expressed giving it a thread-like shape (hence the name flesh-worms).
What is the usual course of comedo?
Chronic. The lesions may persist indefinitely or the condition may be somewhat variable. In many instances, either as a result of pressure or in consequence of chemical change in the sebaceous plugs or of the addition of a microbic factor, inflammation is excited and acne results. The two conditions are, in fact, usually associated.
Fig. 8.
