Penile ulcers are open sores on the penis that can arise from infections, inflammatory conditions, physical trauma, medications, or rarely, cancer. The most common infectious cause worldwide is herpes simplex virus, though syphilis, chancroid, and newer concerns like mpox have complicated the picture. Because so many different conditions produce sores that look similar to the naked eye, a penile ulcer almost always requires laboratory testing to identify the actual cause, and treating based on appearance alone frequently misses the mark.
Herpes Simplex Virus Is the Leading Infectious Cause
Herpes simplex virus (HSV) is the most common infectious cause of genital ulceration, and many infections are asymptomatic, meaning the virus can be passed along without the carrier knowing they have it.1PubMed. Common skin disorders of the penis The majority of genital herpes cases are caused by HSV-2, but HSV-1 (the type usually associated with cold sores around the mouth) can also cause genital ulcers, typically after oral-genital contact.2International Journal of Research in Medical Sciences. Occurrence of genital ulcer due to herpes simplex virus type-1 (HSV-1) in attendees of a regional centre for sexually transmitted infections, central India HSV-1 genital infections tend to recur less frequently, cause milder symptoms, and shed virus less often between outbreaks compared to HSV-2.
A first herpes outbreak on the penis usually produces clusters of small, painful blisters that rupture into shallow ulcers. They can be accompanied by fever, body aches, and swollen lymph nodes in the groin. Recurrent episodes tend to be shorter and less severe. The ulcers typically heal on their own within two to four weeks in a first episode and faster during recurrences, though antiviral medications like acyclovir and valacyclovir shorten healing time and reduce viral shedding.
Syphilis and Its Deceptive Chancre
Primary syphilis classically presents as a single, painless ulcer, called a chancre, appearing at the site of infection roughly three weeks after exposure.3PubMed Central. Multiple primary penile chancre: A re-emphasize Because it does not hurt, people sometimes ignore it or assume it is harmless. The chancre has a clean, firm base and well-defined edges, and it heals on its own within a few weeks even without treatment. That spontaneous resolution is misleading: the infection is still progressing silently into secondary and eventually tertiary stages if left untreated.
The textbook picture of a single painless sore does not always hold. Multiple chancres can appear, and when they do, they are easily confused with herpes, chancroid, or drug reactions.4PubMed Central. Multiple primary penile chancre: A re-emphasize In a five-year study of 244 men with confirmed primary syphilis, extragenital sores were common, particularly in men who have sex with men.5Sexually Transmitted Infections. Clinical and laboratory features of 244 men with primary syphilis: a 5-year single-centre retrospective study Syphilis rates have been climbing in many countries over the past decade, making it a diagnosis that clinicians need to keep near the top of the list.
Other Sexually Transmitted Infections That Cause Ulcers
Chancroid, caused by the bacterium Haemophilus ducreyi, produces one or more painful ulcers with soft, ragged edges and a purulent base. It is uncommon in high-income countries but remains a concern in parts of sub-Saharan Africa and Southeast Asia. Chancroid can also co-occur with other infections acquired from the same exposure. One documented case involved a man who simultaneously developed painful genital ulcers from chancroid and urethral discharge from gonorrhea after a single sexual contact.6PubMed. Co-occurrence of chancroid and gonorrhea
Granuloma inguinale, also called donovanosis, is caused by the bacterium Klebsiella granulomatis and tends to present as a slowly enlarging, painless ulcer with beefy-red granulation tissue. In one reported case, a young man developed a well-defined, nontender ulcer on the penile shaft and corona about a month after unprotected intercourse. Tissue staining revealed the characteristic Donovan bodies inside immune cells, confirming the diagnosis.7PubMed Central. Granuloma inguinale diagnosed on the bedside Without treatment, donovanosis ulcers can grow progressively and destroy tissue over months. Lymphogranuloma venereum, caused by specific strains of Chlamydia trachomatis, is a rarer cause of genital ulceration, sometimes detected alongside other infections in multiplex testing of ulcer swabs.8PubMed Central. Use of a Multiplex PCR Assay To Assess the Presence of Treponema pallidum in Mucocutaneous Ulcerations in Patients with Suspected Syphilis
Mpox as a Newer Consideration
Mpox (formerly monkeypox) became a global concern during the 2022 outbreak and has since been recognized as a cause of genital and penile ulcers. In one case from Japan, a man developed prominent penile swelling and persistent ulcers at the coronal sulcus of the penis. The swelling resolved after about four weeks, but the ulcer and associated pain persisted for more than two months before finally healing.9PubMed. Human mpox presenting with penile edema and ulcer: A case report In another case, a man returning from travel presented with multiple crusted, umbilicated papulopustules on the glans, shaft, and root of the penis, along with fever and fatigue.10CosmoDerma. Mpox: A recent addition to the differential diagnosis of genital ulcer disease
Mpox lesions often begin as papules or pustules that crust over and can ulcerate, and they may appear alongside lesions elsewhere on the body (limbs, face, or perianal area). The prolonged healing time makes mpox ulcers particularly burdensome, and clinicians now include it in the differential when evaluating genital sores, especially in people who report skin-to-skin contact during sex.
Non-Sexual Infections and Lipschütz Ulcers
Not every penile ulcer traces back to a sexually transmitted infection, and this matters enormously for the person sitting in the exam room worrying about what their diagnosis implies. Epstein-Barr virus (EBV), the virus behind mononucleosis, can cause genital ulcers that have nothing to do with sexual contact. While most of the published cases involve vulvar ulcers in young women, the corresponding condition in males, sometimes presenting as acute painful scrotal or penile ulcers following a throat infection, has been recognized since the 1950s.11PubMed. Lipschütz genital ulcer revisited: is juvenile gangrenous vasculitis of the scrotum the male counterpart? These are sometimes called Lipschütz ulcers. Because EBV is not necessarily sexually transmitted, identifying it as the cause can spare patients from the psychological weight of a sexually transmitted disease diagnosis.12PubMed. Genital ulcers caused by Epstein-Barr virus
This distinction is especially relevant for adolescents and younger patients who develop genital ulcers during an acute EBV illness. The ulcers typically resolve as the viral infection clears, often without specific treatment beyond supportive care.
Inflammatory and Autoimmune Causes
Behçet’s disease is a chronic inflammatory condition that causes recurrent, painful ulcers in the mouth and on the genitals, along with skin lesions and, in some cases, eye inflammation.13PubMed Central. Behçet’s disease, painful genital ulcerations and steroid pulse therapy The genital ulcers tend to flare and remit unpredictably. Behçet’s is considered a systemic vasculitis, meaning it involves inflammation of blood vessels throughout the body, and genetic factors play a significant role in who develops it.14PubMed. Behçet Disease: An Update for Dermatologists Diagnosis is clinical, based on the pattern of recurrent oral ulcers plus other characteristic features. There is no single lab test that confirms it, which can make the road to diagnosis frustrating.
Lichen planus, another inflammatory skin condition, can affect the genitals and produce eroded, ulcerated, or white plaques on the glans penis.15PubMed Central. Treatment strategies for erosive genital lichen planus: A systematic review of therapeutic modalities and emerging breakthroughs Erosive genital lichen planus can be chronic and uncomfortable, and treatment usually involves topical immunosuppressants. Pyoderma gangrenosum is a rarer inflammatory condition that has been reported on the penis as well: rapidly enlarging, painful ulcers that worsen despite antibiotics, eventually diagnosed through biopsy.16PubMed Central. Penile pyoderma gangrenosum
Medications and Fixed Drug Eruptions
Certain medications can cause a localized skin reaction called a fixed drug eruption that appears in the same spot every time the drug is taken. The penis is one of the most common locations for this reaction. The lesion typically starts as a round, dusky-red patch that may blister and erode into an ulcer. In a case series, children treated with the antihistamine hydroxyzine developed fixed drug eruptions on the penis that resolved completely once the medication was stopped.17PubMed. Fixed drug eruption of the penis due to hydroxyzine hydrochloride Other commonly implicated drugs include certain antibiotics (trimethoprim-sulfamethoxazole, tetracyclines), nonsteroidal anti-inflammatory drugs, and some over-the-counter pain medications. The hallmark clue is recurrence in the exact same location with repeated exposure. Once the offending drug is identified and discontinued, the eruption heals, though it may leave behind a dark discolored spot.
Physical Trauma and Self-Inflicted Injury
Not all penile ulcers have an infectious or inflammatory cause. Mechanical trauma, including vigorous sexual activity, zipper injuries, and friction from clothing, can produce breaks in the skin that ulcerate. One published case described a genital ulcer resulting from mild trauma during oral-genital contact.18PubMed. Penile ulcer from traumatic orogenital contact In clinical practice, a traumatic ulcer usually has an irregular shape, a clear temporal relationship to an event, and no associated systemic symptoms like fever or lymph node swelling.
Self-inflicted injuries represent a less common but clinically important cause. A case report documented a penile ulcer caused by a rubber band constriction injury, which required urgent management to prevent complications like gangrene.19PubMed Central. Self-inflicted genital ulcer: An intriguing case report Clinicians encountering atypical or unexplained penile ulcers should keep self-harm in mind, particularly in patients with psychiatric histories.
When to Worry About Cancer
Most penile ulcers are caused by infections or inflammation, but a sore that does not heal despite appropriate treatment warrants further investigation. All suspicious non-healing or ulcerating lesions on the genitals should undergo pathologic evaluation to rule out malignancy.20Sexual Medicine Reviews. Male Genital Dermatology: A Primer for the Sexual Medicine Physician Penile cancer is rare overall, but risk factors include lack of circumcision, chronic inflammation, phimosis, HPV infection, and smoking. Squamous cell carcinoma accounts for the vast majority of penile cancers. An ulcer that persists for weeks without obvious cause, particularly in a man over 50 with risk factors, should prompt a biopsy.
Why Diagnosis by Appearance Alone Falls Short
Doctors have traditionally tried to diagnose genital ulcers by their appearance: painless and firm means syphilis; painful and soft means chancroid; clusters of small blisters mean herpes. This approach, known as syndromic management, sounds intuitive but performs poorly in practice. A systematic review and meta-analysis found that diagnosing herpes based on clinical appearance alone had a sensitivity of only about 44%, while syndromic diagnosis of syphilis caught only about 53% of cases. Chancroid detection fared somewhat better at around 72% sensitivity but with specificity of only about 53%.21Frontiers in Medicine. The Diagnostic Accuracy of Syndromic Management for Genital Ulcer Disease: A Systematic Review and Meta-Analysis In plain terms, relying on how an ulcer looks misses roughly half of herpes and syphilis cases.
Laboratory testing has become the standard of care. Multiplex PCR assays can simultaneously test an ulcer swab for multiple pathogens, including herpes, syphilis, and sometimes lymphogranuloma venereum. In one evaluation across multiple public health labs, multiplex PCR showed high agreement for both HSV and syphilis detection, and it identified syphilis in about 7% of specimens that had been submitted only for herpes testing, meaning those syphilis cases would have been missed entirely without the broader panel.22PubMed Central. Evaluation of a laboratory developed multiplex real-time PCR assay for diagnosis of syphilis, herpes, and chancroid genital ulcers in four public health laboratories in the United States Another study of suspected syphilis ulcers found that about 45% tested positive for the syphilis bacterium, about 21% tested positive for HSV, roughly 5% had coinfections with more than one pathogen, and about 31% came back negative for everything on the panel.23PubMed Central. Use of a Multiplex PCR Assay To Assess the Presence of Treponema pallidum in Mucocutaneous Ulcerations in Patients with Suspected Syphilis
For syphilis specifically, PCR-based testing of the ulcer itself outperforms older methods. In one study, PCR detected the syphilis bacterium in about 94% of confirmed primary syphilis cases, compared to about 60% for darkfield microscopy.24Sexually Transmitted Infections. Clinical and laboratory features of 244 men with primary syphilis: a 5-year single-centre retrospective study Darkfield microscopy, while still useful in settings where PCR is not available, has been declining as a primary tool.25PubMed Central. Use of Treponema pallidum PCR in testing of ulcers for diagnosis of primary syphilis Blood tests for syphilis (serology) are important too, but they can be negative during the earliest weeks of primary infection. In one study, nearly half of patients with a positive darkfield result had negative serology at the time, highlighting the value of direct testing of the ulcer itself during early disease.26Enfermedades Infecciosas y MicrobiologÃa ClÃnica (English Edition). Is dark-field microscopy still useful for the primary syphilis diagnosis in the 21ST century?
The Connection Between Genital Ulcers and HIV
Genital ulcers do more than cause local discomfort. They disrupt the skin barrier and create a direct route for other infections to enter the bloodstream, and the most consequential of these is HIV. A study of homosexual men found that a history of syphilis, evidence of HSV-2 infection, and genital ulcer disease were all independently associated with HIV infection. The pattern suggested that HSV-2 infection preceded HIV acquisition, meaning the ulcerative disease created vulnerability rather than the other way around.27JAMA. The Association Between Genital Ulcer Disease and Acquisition of HIV Infection in Homosexual Men
The risk is not limited to men who have sex with men. A prospective study of heterosexual men found that those with a genital ulcer had roughly three times the risk of HIV seroconversion compared to those without one. Chancroid and repeated acquisition of sexually transmitted infections during follow-up were particularly strong risk factors.28PubMed. HIV-1 seroconversion in patients with and without genital ulcer disease. A prospective study This bidirectional relationship, where genital ulcers facilitate HIV transmission and HIV in turn worsens other genital infections, makes prompt diagnosis and treatment of any penile ulcer a public health priority, not just a personal one.
The Psychological Weight of Genital Ulcers
A penile ulcer can carry an emotional burden that outlasts the physical sore. Genital herpes is the best-studied example: because it recurs and has no cure, the diagnosis often triggers significant anxiety and shame. In one study of people living with chronic genital herpes, the point prevalence of moderate to severe anxiety was 32%. Stigma shaped whether people disclosed their diagnosis to sexual partners, and that stigma was driven by socially constructed ideas about the infection rather than its actual medical severity.29PubMed. Chronic genital herpes and disclosure…. The influence of stigma Taking suppressive antiviral medication did not reduce anxiety scores, suggesting the distress was tied to the label and the social meaning of the diagnosis more than to the physical symptoms themselves.
This dynamic extends beyond herpes. Any genital ulcer, regardless of cause, can provoke fear about sexual health, relationship fallout, and social judgment. For conditions like EBV-related Lipschütz ulcers, where no sexual transmission is involved, the emotional relief of a correct diagnosis can be as meaningful as the physical treatment. This is one more reason accurate laboratory testing matters: knowing the actual cause helps patients understand what they are dealing with, how to talk about it, and what to expect going forward.
When Penile Ulcers Appear in Younger Patients
Genital ulcers in adolescents and children raise particular diagnostic and social challenges. While sexual abuse must always be considered and sensitively evaluated, non-sexually transmitted causes exist and should not be overlooked. Lipschütz ulcers from acute EBV infection, as described earlier, can occur in young males as acute painful scrotal or penile ulcers following pharyngeal infections.30PubMed. Lipschütz genital ulcer revisited: is juvenile gangrenous vasculitis of the scrotum the male counterpart? Fixed drug eruptions from medications are another non-sexual cause documented in pediatric patients.31PubMed. Fixed drug eruption of the penis due to hydroxyzine hydrochloride Behçet’s disease can also present in adolescence, typically with recurrent oral and genital ulcers.
Clinicians evaluating genital ulcers in younger patients must balance thoroughness with sensitivity. Testing for sexually transmitted infections is appropriate when clinical suspicion exists, but anchoring exclusively on STI diagnoses can delay recognition of inflammatory or viral causes that require a completely different treatment approach. Parents and patients benefit from knowing that not all genital ulcers are sexually transmitted, and a careful workup can sort this out.