What should you know about classic lichen planus?

The rash often appears as small, firm, flat-topped bumps with a violet, reddish or brown tone. It may affect the wrists, ankles, lower back or lower legs, and scratching can create new areas along irritated skin. Fine white lines may cross the surface of some bumps. The condition is not the same as a skin infection, and its appearance can overlap with other rashes, so an examination helps confirm the diagnosis. Skin colour changes can remain after the active inflammation settles.

Arrange a dermatology assessment if a new itchy, persistent bump rash is spreading or interfering with sleep. Treatment may include a prescribed steroid cream such as [Topical Corticosteroids](/treatments/medical-dermatology/topical-corticosteroids/); more extensive disease may prompt discussion of [Oral Corticosteroid Treatment](/treatments/medical-dermatology/oral-corticosteroid-therapy/). Use a fragrance-free moisturiser, keep nails short, and choose lukewarm showers. Avoid vigorous rubbing or picking, which can aggravate the inflammation. You can compare related concerns such as [Itchy Skin](/symptoms/itchy-skin/) and [Skin Bumps](/symptoms/skin-bumps/) while preparing for an appointment.

Seek prompt assessment for sores in the mouth or genital area, painful blisters, rapidly worsening swelling, or difficulty eating or urinating. Arrange a routine review when the rash persists, leaves marked colour changes, or affects the scalp, nails or eyes. A clinician may need to inspect several body sites and sometimes take a small skin sample because similar-looking eruptions have different treatments.

Could this be classic lichen planus or another itchy bump rash? Which areas should I monitor? How should I apply the prescribed treatment, and what should I do if the skin becomes sore or infected? Could medicines or another health condition be contributing?