  Geographic tongue (GT) is a benign condition affecting approximately 2% of
the population, whereby the papillae covering the upper part of the tongue are
lost due to a slowly expanding inflammation. The resultant dynamical appearance
of the tongue has striking similarities with well known phenomena observed in
excitable media, such as forest fires, cardiac dynamics and chemically-driven
reaction-diffusion systems. Here we explore the dynamics associated with GT
from a dynamical systems perspective, utilizing cellular automata simulations.
We emphasize similarities with other excitable systems as well as unique
features observed in GT. Our results shed light on the evolution of the
inflammation and contribute to the classification of the severity of the
condition, based on the characteristic patterns observed in GT patients.
