The oral cavity may be affected directly, as occurs in Addison’s disease, which leads to changes in oral pigmentations of the tongue secondary to hypovitaminosis B complex. Inflammatory lesions are the most common type and have many subcategories. [homesteadschools.com]

Rogério O Gondak, Rogério da Silva Jorge, Jacks Jorge, Marcio A Lopes, Pablo A Vargas (2012) Oral pigmented lesions: Clinicopathologic features and review of the literature. Med Oral Patol Oral Cir Bucal 17(6): e919-e924. [lupinepublishers.com]

In the mouth, the lips are dry and fissured, the tongue appears red with prominent papillae (strawberry tongue) [53]. [rroij.com]

[…] of papillae on the surface of the tongue (strawberry tongue) and intense erythema of the mucosal surfaces. [140] Ulceration in the oral cavity is a common presenting sign. [141] The labia may appear cracked, cherry-red, swollen, or hemorrhagic. [127] [emedicine.medscape.com]

The pharyngeal congestion in scarlatina and the Koplik spots in measles aid materially in diagnosis before the skin eruption appears. To review the literature of mouth eruptions and to [jamanetwork.com]