Differential Diagnosis for New Mouth Sores
Single Most Likely Diagnosis
- Aphthous Ulcers: These are the most common cause of mouth sores and are often recurrent. They can be triggered by stress, trauma, or certain foods.
Other Likely Diagnoses
- Herpes Simplex Virus (HSV): HSV can cause painful mouth sores, especially on the lips (cold sores) or inside the mouth.
- Hand, Foot, and Mouth Disease: This is a viral illness that can cause mouth sores, especially in children.
- Oral Candidiasis (Thrush): This fungal infection can cause white patches and mouth sores, especially in immunocompromised patients or those taking antibiotics.
- Trauma: Accidental bites or other forms of oral trauma can cause mouth sores.
Do Not Miss Diagnoses
- Oral Cancer: Although less common, mouth sores can be a sign of oral cancer, especially in patients with a history of smoking or tobacco use.
- Lichen Planus: This autoimmune condition can cause mouth sores and ulcers, and can be associated with other systemic diseases.
- Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis: These are life-threatening conditions that can cause mouth sores, skin blisters, and other systemic symptoms, often triggered by medications or infections.
- HIV/AIDS: Mouth sores can be a sign of immunocompromise, and patients with new mouth sores should be screened for HIV if risk factors are present.
Rare Diagnoses
- Pemphigus Vulgaris: This is a rare autoimmune disease that can cause mouth sores and blisters.
- Erythema Multiforme: This is a rare skin condition that can cause mouth sores and other systemic symptoms, often triggered by infections or medications.
- Behçet's Disease: This is a rare autoimmune disorder that can cause mouth sores, genital ulcers, and other systemic symptoms.
Workup in the Emergency Department
The workup for new mouth sores in the emergency department should include:
- A thorough history and physical exam to identify potential causes and risk factors
- Laboratory tests such as complete blood count (CBC), blood cultures, and HIV screening if indicated
- Imaging studies such as CT or MRI if oral cancer or other serious conditions are suspected
- Consultation with specialists such as dentistry, otolaryngology, or infectious disease if necessary.