Black hairy tongue – pictures, symptoms, causes, treatment, Black hairy tongue - what is it? symptoms, pictures, causes, treatment of black hairy tongue. it is a harmless oral condition which gives the tongue a furry, dark. Hairy tongue (black, white) - causes, treatment and pictures, Black hairy tongue is also referred to as lingua villosa nigra. it is generally a painless and harmless condition of the tongue characterized by the development of.