Drug-induced lichenoid reactions (also known as "Lichenoid drug eruption" and "Drug-induced lichen planus") are skin eruptions that occur after ingestion, contact, or inhalation of certain chemicals, with the most common inducers being gold salts, beta blockers, antimalarials, thiazide diuretics, furosemide, spironolactone, and penicillamine. As well as systemic side effects of hypoglycaemic drugs such as Metformin.

Restated, lichenoid drug reactions occur as type IV (delayed) allergic reactions to medications for high blood pressure, heart disease

Heart disease

Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...

 and arthritis

Arthritis

Arthritis is a form of joint disorder that involves inflammation of one or more joints....

. These lichenoid reactions are referred to as lichenoid mucositis (of the mucosa) or dermatitis (of the skin). Allergic reactions to amalgam

Amalgam (dentistry)

Amalgam is an alloy containing mercury. The term is commonly used for the amalgam employed as material for dental fillings, which consists of mercury , silver , tin , copper , and other trace metals...

 (metal alloys) dental restoration

Dental restoration

A dental restoration or dental filling is a dental restorative material used to restore the function, integrity and morphology of missing tooth structure. The structural loss typically results from caries or external trauma. It is also lost intentionally during tooth preparation to improve the...

s (fillings) may contribute to the oral lesions identical, both clinically and histologically, to oral lichen planus

Oral lichen planus

Mucosal lichen planus, or oral lichen planus , is an inflammatory auto-immune disease that affects oral mucosa, with or without the involvement of the skin and other mucous membranes.- Epidemiology :...

 lesion

Lesion

A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...

s, and a systematic review

Systematic review

A systematic review is a literature review focused on a research question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. Systematic reviews of high-quality randomized controlled trials are crucial to evidence-based medicine...

found that many of the lesions resolved after the restorations were replaced.