Initial assessment
When faced with an ulcer in the anogenital region, the first step is to determine whether the lesion is painful or painless. This criterion guides the diagnostic suspicion and defines the subsequent investigation.
Painful ulcers
The presence of pain should raise different diagnostic possibilities:
Genital herpes
The observation of grouped vesicles or superficial erosions that progress to ulcers suggests genital herpes. It is a recurrent infection, marked by intense pain and local symptoms. Treatment may be with aciclovir or valaciclovir, both for primary infection and recurrences, with the possibility of suppressive therapy in cases of frequent relapses. During pregnancy, aciclovir is considered safe after the first trimester.
Lipschütz ulcers
When pain occurs abruptly, associated with fever, myalgia, odynophagia or another recent systemic viral illness, Lipschütz ulcers should be considered. These occur mainly in adolescents and young adult women, often after viral infections such as Epstein–Barr virus. They are large, painful ulcers with exudate and cause marked discomfort. Management is symptomatic and may include topical lidocaine, topical corticosteroid therapy with clobetasol and, in severe cases, systemic corticosteroid therapy. In refractory situations, drugs such as colchicine, pentoxifylline or dapsone may be considered under specialist supervision.
Chancroid
The presence of a painful ulcer with a soft base, necrotic or purulent appearance, irregular borders and painful inguinal lymphadenopathy suggests chancroid. Although rare in Portugal, this sexually transmitted infection should be considered in the appropriate epidemiological context. Treatment may include azithromycin, ceftriaxone, ciprofloxacin or erythromycin. In the presence of fluctuant inguinal buboes, drainage or aspiration may be required.
Painless ulcers
When the lesion is painless, assessment should take into account the number of ulcers and the characteristics of the lymphadenopathy.
Primary syphilis
The presence of a single, painless ulcer with indurated borders and a clean base is suggestive of primary syphilis. This lesion, known as a hard chancre, may go unnoticed and is often associated with bilateral, painless and mobile lymphadenopathy. The treatment of choice is benzathine penicillin. In allergic patients, doxycycline, ceftriaxone or, as a last resort, azithromycin may be used.
Lymphogranuloma venereum
If the patient presents with painful fluctuant lymphadenopathy appearing weeks after an initial subtle or unidentified ulcer, lymphogranuloma venereum should be considered. This infection is caused by invasive serovars of Chlamydia trachomatis. Lymphadenopathy is often unilateral and painful and may progress to fistulising buboes. Treatment is with doxycycline, erythromycin or azithromycin. In cases with fluctuation, aspiration drainage is recommended.
Granuloma inguinale (Donovanosis)
An extensive, painless ulcer with a destructive and highly vascular appearance suggests granuloma inguinale. Treatment should include azithromycin, doxycycline, erythromycin or trimethoprim-sulfamethoxazole, maintained for at least three weeks or until complete resolution of the lesions.
Complementary assessment
Regardless of the clinical suspicion, a global assessment should be performed: detailed clinical history, complete physical examination, screening for other sexually transmitted infections and possible referral to specialist care. Until proven otherwise, all genital ulcers should be considered infectious in origin.
Laboratory investigation should obligatorily include: HIV 1 and 2, HSV 1 and 2, hepatitis B (HBV), treponemal test and VDRL.
Treatment of the sexual partner
The sexual partner should be treated even if asymptomatic, except in the case of genital herpes, where treatment is recommended only if symptoms are present.
Differential diagnosis and empirical treatment
The definitive diagnosis depends on laboratory investigation. In cases where uncertainty persists in the differential diagnosis — particularly between syphilis and chancroid, or between lymphogranuloma venereum and granuloma inguinale — empirical treatment targeting more than one aetiology simultaneously should be considered.
