History of Present Illness (HPI)

The patient is a [insert age]-year-old female presenting with painful sores on the top and bottom lip and in her mouth and gums for the past 3 days. She recently discovered that her boyfriend was unfaithful, which has led to her concern about sexually transmitted infections (STIs) and her request for testing.

Differential Diagnosis

• Single Most Likely Diagnosis
  • Herpes Simplex Virus (HSV) Infection: Given the patient's symptoms of painful sores on the lips and in the mouth, along with the recent stressor of discovering her boyfriend's infidelity, which could have triggered an outbreak, HSV infection is a highly plausible diagnosis. The stress and potential immunosuppression could have reactivated a latent infection.
• Other Likely Diagnoses
  • Aphthous Ulcers: These are common, recurrent, and can be triggered by stress, among other factors. The patient's recent emotional distress could be a contributing factor.
  • Canker Sores: Similar to aphthous ulcers, canker sores can be painful and appear in the mouth, potentially triggered by stress or minor mouth injury.
  • Syphilis (Primary): Given the patient's concern about STIs, primary syphilis, which can present with a single, painless chancre, should be considered, although the painful nature of her sores makes this less likely.
• Do Not Miss Diagnoses
  • Gonorrhea or Chlamydia: Although less commonly presenting with oral sores, these STIs can cause pharyngitis and should not be missed due to their potential for serious complications if untreated.
  • HIV Infection: Acute HIV infection can present with a variety of symptoms, including oral ulcers. Given the patient's concern about STIs, testing for HIV is crucial.
• Rare Diagnoses
  • Behçet's Disease: A rare condition characterized by recurrent oral ulcers, along with genital ulcers and uveitis. It's less likely but should be considered if other diagnoses are ruled out and the patient has a history of recurrent oral and genital ulcers.
  • Erythema Multiforme: A skin condition that can be triggered by infections (including HSV) or medications, characterized by target lesions and sometimes oral ulcers. It's less common and typically associated with more widespread skin lesions.