LICHEN PLANUS

Synonym: Lichen ruber planus.

Lichen planus is a chronic inflammatory derma-
tosis, the elementary lesions of which consist of
small polygonal, flat, glistening, red or bluish red
papules, some slightly umbilicated, which tend to
coalesce and form irregular and raised slightly scal-
ing patches. Papules which are at first about the
size of a pinhead often increase by peripheral
growth. Involution may proceed in the center or at
one edge of a large papule or of a small patch and
result in the formation of rings or crescentic figures.
New papules often appear along a scratch. On a
fully developed patch is to be made out a network of
delicate gray striae which is characteristic of the
disease. While the earliest rash is sometimes of a
rose red color the larger, older lesions nearly always
shade into a violaceous or purple hue. Where the
eruption has disappeared a brownish pigmentation is
left to be slowly absorbed. Rarely there is atrophy
of the skin. Lichen verrucosus is the form which
occurs most frequently upon the legs. The patches
become more elevated, infiltrated, rough and scaly.
Individual papules may be hard to find, but the gray
striations are well marked. Such lesions persist in-
definitely, with but slight variation, and are resistant
to treatment. The favorite localities for lichen pla-
nus are the flexor surfaces of the wrists and fore-
arms, the shins and about the malleoli, and the gen-
itals, especially the scrotum, glans and prepuce. The
disease is uncommon on the face, palms and soles,
but any part of the body may be attacked, even the
mucous membranes on which the lesions appear as

white plaques of thickened epithelium. The disease
never becomes universal; even in extreme cases
there are always some free areas. Lichen planus
is infrequently met with among children. Itching is
usually intense; it may be slight, but is very rarely
entirely absent. The disease is very chronic, per-
sisting for months even under treatment. It disap-
pears slowly, often with recrudescentes and relapses.

**DIAGNOSIS:** The polygonal papules and the gray striations are pathognomonic. Large patches may resemble *psoriasis*, but the distribution is different, scaling is much less marked and the scales are much more adherent; the purple color is peculiar to lichen; psoriasis spreads by peripheral extension, lichen by the accretion of new papules; psoriasis rarely itches, intensely. A patch of *eczema* is almost always moist at some time in its development, while oozing never occurs in lichen planus; moreover, the papules of eczema are rounded or acuminate and frequently associated with vesicles or pustules.

**TREATMENT:** Attention to hygiene is of importance. Internally arsenic, in full doses, is often of value. Mercury also seems to help. The two may be administered together in the form of Donovan's solution. Externally antipruritic remedies should be employed. Tarry preparations are the best, as for example five per cent oil of cade in zinc oxid ointment; the percentage of the oil should be increased as the patient is found to become more tolerant. Indolent patches on the legs may require an even stronger remedy, such as a four to eight per cent chrysarobin ointment.

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