Papular Inflammation

Lichen Planus
Lichen planus is a non-contagious affection of the skin, characterized by the development of small, flattened papules, which frequently present a distinct central depression or umbilicus.

Lichen planus is an eruption of pimples, remarkable for their color, their figure, their structure, their habits of isolated and aggregated development, their habitat, their local and chronic character, and for the melasmic stains which they leave behind them when they disappear.

The color of the pimples is a dull crimson-red, more or less livid, and suffused with a purplish or lilac tinge.

In figure the papulae are flattened, smooth, and depressed on the summit, angular in outline, but slightly elevated, and of a size ranging between one and three lines in diameter; the flatness is rendered more conspicuous by the summit of the papule being occupied by a thin, horny, semi-transparent lamina of cuticle, depressed on the surface, and marked by the aperture of a follicle, which represents a sort of hilum. In structure, the papule of lichen planus is a hyperaemia with exudation, surrounding a follicle and surrounding a thin layer of horny, transparent cuticle; while the aperture of the follicle and its conical epidemic plug are visible in the center of the horny plate. The horny covering is in nowise a scale; it rises and falls with the papule and neither separates nor exfoliates.


Lichen planus presents two principal forms of manifestation - discrete and aggregate.


The habitat of the eruption is also characteristic of the identity of lichen planus. It is pretty constantly met with on the front of the forearm, just above the wrist; in the hollow of the loins; on the lower half of the abdomen; on the hips; around the knees, particularly over the mass of the vastus internus muscle; on the forearms and calves of the legs, and in women around the waist and in the grooves occasioned by the garters. We have seen it also, but less frequently, on the palms of the hands and soles of the feet; and in two instances on the tongue, the buccal membrane, and the mucous lining of the fauces.

Lichen planus is essentially chronic and local in its habits. In distribution it is generally symmetrical, but occasionally is limited to one side of the body; sometimes occurring on one side in the upper extremity, and on the other in the lower. It has no constitutional symptoms of its own, and frequently prevails with very little disturbance of any kind.

Of course, the totality of the characters above noted are not to be found in every case. The characteristic features, however, are the flattened umbilical papules. This central depression may not be noted in every papule; and when a number of them have run together and coalesced, it is commonly absent, and met with only on those in the neighbourhood of, but which do not form a part of, the patch.

The duration of the affection is indefinite. It may undergo resolution, and the papules disappear after three or four months, or, especially when the eruption is extensive, may resist the best-directed treatment for a year or more.