What should you know about etiology of lichen planus?

The exact trigger is often unclear. The condition is not caused by poor hygiene and is not contagious. Immune activity can produce itchy, flat-topped or shiny bumps, areas of scaling, or changes inside the mouth, genitals, nails, or scalp. Some medicines can cause a similar-looking lichenoid eruption, so a clinician will review prescriptions, supplements, and the timing of any new rash.

A diagnosis may involve examining the pattern and, when needed, taking a small skin sample. A rash alone cannot establish the cause; eczema, psoriasis, medication reactions, and other conditions can resemble it.

Arrange a dermatology assessment if bumps or patches persist, recur, or affect the mouth or nails. Keep a list of medicines and note when the first changes appeared. Avoid scratching, harsh scrubs, and fragranced products that can irritate inflamed skin. Treatment is chosen for the affected site and may include /treatments/medical-dermatology/topical-corticosteroids/ or, for more extensive disease, /treatments/medical-dermatology/oral-corticosteroid-therapy/.

Seek prompt medical advice for painful mouth sores, difficulty eating or drinking, eye symptoms, rapidly spreading blistering, or signs of infection such as increasing warmth, swelling, pus, or fever. Persistent /symptoms/itchy-skin/ or unexplained /symptoms/skin-bumps/ also deserves an examination.

Could a medicine be causing a lichenoid reaction? Do I need a biopsy or an examination of my mouth, nails, scalp, or genital skin? Which treatment fits the location and severity, and how should it be monitored?