Addisonian Pigmentation of the Oral Mucosa

Cutaneous pigmentation is a hallmark of Addison disease. When present, the hyperpigmentation generally localizes to sun-exposed surfaces. This case highlights a less well-recognized cutaneous feature that is pathognomonic for the disease: oral mucous membrane hyperpigmentation. We describe this unique type of discoloration in detail and contrast it with other forms of oral pigmentation.