What should you know about lichen planus caused by?

The immune system becomes active in the upper layers of skin and can produce itchy, firm bumps or patches. In many people, no single trigger is identified. Certain medicines can cause a lichenoid reaction that resembles lichen planus, and contact with some dental materials may be relevant when lesions affect the mouth. Skin injury or repeated scratching can lead to new lesions developing along irritated areas. These associations do not mean that stress, food or a hygiene problem caused the condition, and they should not be used to self-diagnose.

Tell your clinician about medicines started before the rash, dental work, supplements and areas repeatedly rubbed or scratched. Do not stop a prescribed medicine without advice; the clinician can decide whether a substitute or monitored change is appropriate. Protect the skin barrier with moisturiser and gentle cleansing. Topical corticosteroids may calm limited inflammation, while oral corticosteroid treatment may be discussed for extensive symptoms. A skin examination, and sometimes a biopsy, can separate lichen planus from look-alike rashes.

Seek medical review for a rash that is spreading, very itchy, painful or not healing. Mouth ulcers, genital soreness, eye discomfort, scalp hair loss, nail distortion, pus, fever or rapidly changing areas need prompt assessment because the affected site may alter the treatment plan.

Could any medicine or dental material be contributing? Does the pattern fit lichen planus or a lichenoid reaction? Would a biopsy help? Should I continue every current medicine while we investigate?