Question

round, small, painless ulcer noted on external labia. What would be three differential diagnosis?

Answer 1

The three differential diagnosis are:

1. Herpes Simplex Virus Infection
2. Syphilis Infection (Tryponema pallidum bacterium)
3. Chancroid (Haemophilus ducreyi bacterium)

Reason: Most of the vulval ulcers are caused by STIs which are caused by Viruses and bacterias. The can be small, round and painless or painful. Other reasons of ulceration are fungal infection which are not round and other autoimmune and inflammatory lesions which are mostly painful.

Thus for a round and painless ulcer, STIs are the main culprits and in STIs the most common causes are Herpes Simplex, Syphilis and Chancroid.