The term cyanamide is applied to both free cyanamide (carbimide) and its calcium salt (calcium carbimide). It is extensively used as a fertilizer, herbicide and chemical intermediate (1). In the medical field, cyanamide was introduced into Canada, Europe and Japan in 1956 as a treatment for chronic alcoholism. It acts by interfering with the hepatic metabolism of ethanol by inhibiting aldehyde dehydrogenase. When this transformation does not take place, there is an increase in acetaldehyde in the blood, resulting in unpleasant sensations (2). The rare adverse skin reactions due to cyanamide include allergic contact dermatitis (3–7), lichen planus (8, 9) and lichen‐oid eruption (9).