Painful genital ulcers
Differential diagnosis
The most likely causes of painful genital ulcers in this case are herpes simplex, chancroid, and syphilis. Granuloma inguinale and lymphogranuloma venereum (LGV) are rare causes of genital ulceration in the United States. A zipper accident or other trauma can cause genital ulceration, but the patient should be able to give a clear history of such an event.
By epidemiology alone, the order of likelihood for the cause of any genital ulceration is herpes, syphilis, then chancroid.
This case points to herpes
Herpes simplex is by far the most common cause of painful genital ulcers in the United States; at least 50 million people have genital herpes simplex virus (HSV) infection1 The features of this case pointing to herpes are the appearance of multiple ulcers, the tingling pain that preceded the ulcers, and the history of a possible episode in the preceding year. While it would be helpful to have a history of blisters that preceded the ulcers, the evidence still points to herpes as the most likely diagnosis.
Could it be syphilis?
While the primary chancre of syphilis is classically described as painless, the patient with syphilis may experience pain. Syphilis tends to present as a single ulcer but may cause multiple ulcers.
Why not chancroid?
Chancroid may also cause multiple small painful ulcers. However, the ulcers of chancroid tend to be deeper than those of herpes and bleed more easily.
Other characteristics to look for
All of these sexually transmitted diseases can cause tender painful adenopathy, which is particularly characteristic of chancroid and LGV. Suppurative inguinal adenopathy with painful genital ulcers is almost pathognomonic of chancroid. With LGV, there may be a self-limited genital ulcer at the site of inoculation, which is often gone by the time a patient seeks care. Granuloma inguinale causes painless, progressive ulcerative lesions without regional lymphadenopathy. These lesions are highly vascular (with a characteristic beefy red appearance) and bleed easily on contact.1 While it would be helpful to have a history of blisters that preceded the ulcers, the evidence still points to herpes as the most likely diagnosis.
