Dark Purple Discoloration of Oral Mucosa: Differential Diagnosis

Dark purple discoloration inside the mouth or on lips warrants clinical evaluation. Key etiologies include:

Vascular/Blood-Related

• Trauma/Biting: Hematoma, ecchymosis.
• Vascular lesions: Hemangioma, varix, Kaposi sarcoma (HHV-8, immunocompromised).
• Bleeding diathesis: Thrombocytopenia, anticoagulants, leukemia.

Melanocytic/Pigmented

• Physiologic melanosis: Common in darker skin tones.
• Melanotic macule: Benign focal pigmentation.
• Melanoma: Irregular, changing, ulcerated – biopsy mandatory.
• Peutz-Jeghers syndrome: Mucocutaneous macules + GI hamartomatous polyps.
• Addison's disease: Diffuse mucosal hyperpigmentation (elevated ACTH/MSH).

Exogenous/Medication

• Amalgam tattoo (dental silver impregnation).
• Minocycline, antimalarials (chloroquine), chemotherapy, zidovudine.
• Smoking (smoker's melanosis).

Infectious/Inflammatory

• Herpetic stomatitis, necrotizing ulcerative gingivitis, oral lichen planus.

Action: See a dentist or oral medicine specialist promptly for examination, dermoscopy, and possible biopsy.