Differential Diagnosis for Genital Lesions

When attempting to differentiate between HSV sores and vaginal candidiasis, it's crucial to consider a broad range of potential diagnoses to ensure accurate identification and appropriate treatment. The following categories help organize the differential diagnosis:

• Single Most Likely Diagnosis
  • Herpes Simplex Virus (HSV) infection: This is a common cause of genital ulcers and should be considered highly in the differential due to its prevalence and the presentation of painful vesicles or ulcers.
• Other Likely Diagnoses
  • Vaginal Candidiasis: Characterized by a thick, white discharge and intense itching, candidiasis is a frequent cause of vaginal symptoms and can sometimes be confused with HSV due to overlapping symptoms like redness and irritation.
  • Syphilis (primary): The primary stage of syphilis can present with a single, painless chancre, which might be mistaken for an HSV sore, especially if the patient is unaware of the painless nature of the lesion.
  • Genital warts (caused by Human Papillomavirus, HPV): While typically not painful and more often associated with a visible wart, in some cases, the lesions can be flat and might cause confusion in the differential diagnosis.
• Do Not Miss Diagnoses
  • Lymphogranuloma Venereum (LGV): A sexually transmitted infection caused by certain types of Chlamydia trachomatis, LGV can cause genital ulcers, lymphadenopathy, and potentially severe complications if not treated promptly.
  • Granuloma Inguinale (Donovanosis): Characterized by painless, beefy-red ulcers without lymphadenopathy, this condition is less common but can lead to significant tissue destruction if left untreated.
• Rare Diagnoses
  • Behçet's Disease: A form of vasculitis that can cause genital ulcers, among other symptoms like oral ulcers and eye inflammation. It's rare and might be considered if other diagnoses are ruled out and there are systemic symptoms.
  • Autoimmune disorders (e.g., pemphigus, pemphigoid): These conditions can cause blistering lesions that might resemble HSV sores but are much less common and typically involve the skin and sometimes mucous membranes more broadly.

Each diagnosis has distinct features that can help in differentiation, such as the presence of pain, the nature of the discharge, and associated systemic symptoms. Accurate diagnosis often requires a combination of clinical evaluation, patient history, and laboratory testing.