Development of any disease (be it an oral mucosal disease or any disease in general) always combines the provoking causes on the one side and the susceptibility of the individual (i.e., the given organism’s reaction) that depends largely on his/her genetic predispositions and actual health condition. The etiology of various diseases of the oral mucosa varies – the causes differ in their quality (power), quantity and length of exposure, they can combine or even show synergistic effects. The causes can be classified as local and general or internal and external.

External factors include in particular physical (mechanical, thermal, radiation and electrogalvanic), chemical (toxic) and infectious (viral, bacterial, fungal) causes. While infectious agents may be external, the reaction of the organism still depends on the condition and individual immune reaction of the organism.