Penile erosion refers to the loss of the surface layer of skin on the penis, exposing raw, often painful tissue underneath. Unlike a deep ulcer that penetrates through multiple tissue layers, an erosion is relatively shallow, but the distinction matters less to the person experiencing it than the fact that something is visibly wrong in a sensitive area. The causes range widely, from common infections and inflammatory skin conditions to rare vascular emergencies and even cancer. Because the underlying trigger determines both the urgency and the treatment, understanding what can produce penile erosions is the first step toward getting the right care.
Infections That Cause Penile Erosions
Sexually transmitted infections are among the most frequent causes of erosive lesions on the penis. The two most common culprits are herpes simplex virus (HSV) and the bacterium that causes syphilis, with rarer infections caused by the organisms responsible for chancroid, granuloma inguinale, and lymphogranuloma venereum also playing a role.1PubMed Central. Genital ulcers caused by sexually transmitted agents Herpes is the single most common sexually transmitted infection among people living with HIV, and in that group it can behave quite differently than in otherwise healthy individuals.2British Journal of Dermatology. Chronic erosive herpes simplex virus infection of the penis in a human immunodeficiency virus‐positive man, treated with imiquimod and famciclovir
In people with weakened immune systems, herpes does not always follow its typical pattern of blisters that crust over and heal within a couple of weeks. Instead, it can produce chronic, persistent erosions on the penis that last for months. These lesions are painful, resistant to standard antiviral doses, and carry a higher risk of transmitting both herpes and HIV to partners. There are even reports of chronic erosive herpes developing in AIDS patients shortly after starting antiretroviral therapy, possibly as part of the immune system’s inflammatory response to recovery.3PubMed. Chronic erosive herpes simplex virus infection of the penis, a possible immune reconstitution disease The tissue under the microscope in these cases looks unusual, with a heavy presence of plasma cells and eosinophils rather than the typical viral inflammation pattern, which can make diagnosis tricky if a clinician is not thinking about herpes.
Syphilis produces a different kind of erosion. The classic primary chancre is a single, painless, firm-bordered ulcer that appears at the site of contact, usually the glans or shaft. Because it does not hurt, people sometimes ignore it until it resolves on its own, not realizing the infection is silently progressing. A simple blood test or dark-field microscopy of the lesion can identify syphilis, and early-stage disease responds well to penicillin. The key point for anyone noticing an erosion or sore on the penis is that the absence of pain does not mean the absence of a serious infection.
Inflammatory and Autoimmune Conditions
Not every penile erosion comes from an infection. Several inflammatory skin diseases target genital skin, and because the tissue there is thin and moist, erosions develop more readily than they would on, say, the forearm.
Lichen planus is one such condition. In its erosive form, it produces shiny red patches on the glans that break down into painful erosions. A case study confirmed the diagnosis using dermoscopy, a technique where a clinician examines the skin surface under magnification, followed by a tissue biopsy showing the hallmark microscopic pattern of lichen planus. The patient responded well to topical corticosteroids and oral antihistamines.4PubMed Central. Erosive lichen planus of the glans penis Erosive lichen planus can mimic other conditions closely, including some precancerous lesions, so biopsy is often necessary to sort things out.
Lichen sclerosus is a related but distinct condition, more commonly discussed in women but also affecting men. It typically causes white, thinned patches of genital skin that can crack and erode, especially if left untreated. Research has identified an erosive subtype where the surface breaks down without obvious trauma, favoring the smooth, hairless skin of the glans and inner foreskin. Treatment with potent topical steroids achieves complete resolution in about half of cases, though some patients also need antifungal agents, topical estrogen, or even surgical removal of resistant patches.5PubMed Central. Erosive Lichen Sclerosus—A Clinicopathologic Subtype Men with diabetes appear to be at higher risk for the ulcerated form, and those who are not using any treatment at the time of diagnosis tend to present with worse disease.
Behçet’s disease deserves mention because it can produce painful genital ulcers alongside mouth sores, eye inflammation, and skin lesions. The genital ulcers in Behçet’s are driven by an overactive inflammatory response dominated by neutrophils, and they can occasionally overlap with another neutrophilic skin condition called pyoderma gangrenosum, where the ulcers enlarge aggressively and resist healing.6PubMed Central. Genital Ulcerative Pyoderma Gangrenosum in Behçet’s Disease: A Case Report and Review of the Literature Neither condition has a single definitive lab test, so diagnosis relies on recognizing the overall clinical pattern.
When Erosion Signals Cancer or Precancer
Persistent erosions on the penis that do not respond to antibiotics, antivirals, or steroid creams should raise concern about precancerous or cancerous changes. Squamous cell carcinoma in its early, in-situ stage often appears as small reddish patches or papules with surface erosion, typically under two centimeters.7Anais Brasileiros de Dermatologia. Squamous cell carcinoma of the penis: clinicopathologic study of 34 cases These early lesions are confined to the surface and highly treatable if caught, but their appearance overlaps with multiple benign conditions.
Several precancerous conditions collectively known as penile intraepithelial neoplasia can look almost identical to inflammatory erosions. Erythroplasia of Queyrat presents as moist red plaques on the glans or inner foreskin. Bowen’s disease shows up as a scaly patch on the keratinized shaft skin. Bowenoid papulosis produces small pink or brown papules that can appear almost anywhere on the penis. All three are considered precursors to invasive squamous cell carcinoma. The challenge is that erosive lichen planus and a condition called Zoon’s balanitis can look nearly identical to erythroplasia of Queyrat on visual inspection alone, while psoriasis and genital warts can mimic Bowen’s disease.8Frontiers in Oncology. A comprehensive review of current knowledge on penile squamous cell carcinoma This diagnostic overlap is exactly why biopsy is so important for erosions that persist or look atypical.
Vascular Emergencies and Tissue Death
Some of the most alarming causes of penile erosion involve compromised blood supply, which can progress from surface erosion to full-thickness tissue death rapidly.
Calciphylaxis is a systemic condition seen in roughly one to four percent of people with end-stage kidney disease.9Journal of Vascular Surgery. Revascularization surgery for penile calciphylaxis Calcium deposits build up inside small artery walls, eventually blocking them completely and starving the tissue downstream. On the penis, this presents as painful patches that darken and break down into necrotic wounds. The process is driven by total obstruction of the artery, leading to acute ischemia and dead tissue formation.10PubMed Central. Penile necrosis and calciphylaxis Treatment may involve wound care, correcting calcium and phosphorus imbalances, and in some cases revascularization surgery, but outcomes remain poor for many patients.
Fournier’s gangrene is a necrotizing soft tissue infection of the genitalia and perineum that qualifies as a surgical emergency. It typically starts from a genitourinary or gastrointestinal source and involves multiple types of bacteria working together.11Urologic Clinics of North America. Management of Necrotizing Soft Tissue Infections of the Genitalia What makes it so dangerous is the speed: the infection spreads along tissue planes, destroying blood vessels and causing skin and tissue death at rates that have been measured at two to three centimeters per hour.12PubMed Central. Practical Review of the Current Management of Fournier’s Gangrene Early signs can be deceptively mild, sometimes just swelling, redness, and pain that seem disproportionate to the visible findings, before the skin darkens and breaks down. Aggressive surgical removal of dead tissue combined with broad-spectrum antibiotics is the standard of care, and delays measured in hours worsen survival.13PubMed Central. Fournier’s Gangrene of the Penis: A Rare Entity
Catheter-Related and Traumatic Erosion
For people with spinal cord injuries or other conditions requiring long-term urinary catheters, the catheter itself can erode through penile tissue. Prolonged pressure from an indwelling catheter against the urethral wall and glans gradually wears through the skin, and if the balloon is mistakenly inflated inside the urethra rather than the bladder, severe erosion of the glans and ventral shaft can happen quickly.14PubMed Central. Severe ventral erosion of penis caused by indwelling urethral catheter and inflation of Foley balloon in urethra These injuries are largely preventable through proper catheter placement, routine checks, and periodic catheter changes. There have been calls to classify certain catheter misplacements as “never events” in spinal cord injury care, meaning errors that should be entirely avoidable with proper protocols.
Pediatric penile injuries are a separate concern. In children, the most frequent cause of penile injury overall is circumcision accidents, followed by traumatic accidents, strangulation injuries from hair or thread wrapping around the shaft, and rarely, electrical burns.15PubMed Central. Penile injuries in children While these are not “erosions” in the strict dermatologic sense, they produce surface tissue loss that requires similar wound-management principles.
Drug Reactions That Target the Penis
Fixed drug eruption is an underappreciated cause of penile erosion. In this reaction, the same patch of skin flares up every time a person takes a particular medication. The penis is one of the most common locations for this to occur, and the pattern is distinctive: a round, reddish or dusky patch appears within hours of taking the drug, often blistering and then eroding. A systematic review of male genital fixed drug eruptions found that redness was the predominant sign, present in about 86 percent of cases, while erosions appeared in roughly a third and blisters in about a quarter.16PubMed. Male genital fixed drug eruption: a systematic review After healing, a dark patch of post-inflammatory pigmentation often remains, serving as a clue that connects the current flare to previous episodes. Common triggers include certain antibiotics, anti-inflammatory drugs, and anticonvulsants. The treatment is straightforward: identify and permanently avoid the offending medication.
How Penile Erosions Are Diagnosed
A clinician evaluating a penile erosion starts with a thorough history and physical exam. Key questions include how long the lesion has been present, whether it is painful or painless, whether it recurs, whether the patient has similar sores elsewhere (the mouth, for instance, which would point toward Behçet’s disease or lichen planus), and what medications the patient takes. Sexual history and HIV status are relevant because they shift the probability of certain diagnoses significantly.
Swabs and blood tests help rule in or rule out infectious causes. Herpes can be confirmed with viral culture or PCR testing of the lesion, while syphilis is typically caught on serologic blood tests. For erosions where infection has been excluded or treatment has failed, biopsy is the gold standard. A small sample of tissue is taken under local anesthesia and examined under a microscope. A survey of dermatologists and venereologists found that practices vary when it comes to performing penile biopsies: about a third routinely used epinephrine in the local anesthetic, another group used it sometimes, and nearly half did not use it at all. Complications from the procedure were rare, with only two reported adverse events, both temporary and without tissue damage.17Journal of Clinical and Aesthetic Dermatology. Survey of Dermatologists and Venereologists Shows Varying Approach to Penile Biopsies The takeaway for patients is that penile biopsy, while understandably anxiety-provoking, is a safe and often necessary step.
Dermoscopy, the magnified skin-surface examination mentioned earlier in the context of lichen planus, is increasingly used as a non-invasive first step. It can highlight vascular patterns and surface structures that help a clinician narrow the differential diagnosis before deciding whether biopsy is needed.
The Role of the Penile Microbiome
An emerging area of research looks at the community of bacteria living on penile skin and how shifts in that community relate to inflammation and erosion. In men with balanoposthitis, an inflammatory condition of the glans and foreskin that frequently causes redness and erosion, researchers have found decreased skin hydration and increased pH compared to healthy controls. Two bacterial species, Staphylococcus warneri and Prevotella bivia, were the most abundant in affected men and their levels correlated with disease severity.18PubMed Central. Microbiome Profile in Patients with Adult Balanoposthitis: Relationship with Redundant Prepuce, Genital Mucosa Physical Barrier Status and Inflammation This does not yet translate into specific treatments, but it suggests that maintaining a healthy skin barrier through gentle hygiene and avoiding irritants could play a preventive role. Overwashing with harsh soaps, ironically, may worsen things by disrupting the skin’s natural acidity and moisture balance.
Medical Treatments
The specific treatment for penile erosion depends entirely on the cause. For infectious erosions, targeted antimicrobials are the mainstay: antivirals for herpes, antibiotics for syphilis and bacterial infections. For inflammatory conditions like lichen planus and lichen sclerosus, potent topical corticosteroids are the standard first-line therapy. However, penile skin absorbs topical medications much more readily than skin on most other body sites, which increases both effectiveness and the risk of side effects like thinning skin with prolonged steroid use.
When corticosteroids fail or cause problems, calcineurin inhibitors like tacrolimus offer a promising alternative. In cases of plasma cell balanitis, a chronic inflammatory condition of the glans that produces persistent erosions and is often lumped under the umbrella of Zoon’s balanitis, corticosteroid-resistant disease has responded to a regimen starting with a brief course of topical steroid followed by tacrolimus ointment. In one reported protocol, dramatic improvement appeared within two weeks, with near-complete resolution by six weeks.19PubMed Central. Plasma Cell Balanitis Unresponsive to Topical Corticosteroids: Combined Efficacy of Tacrolimus and Emerging Evidence for Underrecognized Intrinsic Resistance to Corticosteroids Tacrolimus does not thin the skin the way steroids do, making it better suited for long-term use on delicate genital tissue.
Surgical Reconstruction After Severe Tissue Loss
When erosion or necrosis destroys enough tissue that the wound cannot close on its own, surgical reconstruction becomes necessary. Modern approaches often use a staged technique. In the first stage, after all dead or diseased tissue is removed, a dermal regeneration matrix is placed over the wound to create a scaffold for new tissue growth. This stays in place for several weeks under specialized dressings. In the second stage, a skin graft harvested from the thigh or groin is laid over the newly formed tissue bed.20PubMed Central. Penile Reconstruction with Skin Grafts and Dermal Matrices: Indications and Management
A series of patients who underwent this two-stage approach for penile skin loss found that both the dermal matrix and the skin graft took successfully within a week of each procedure. By six months, the grafted skin had gained enough elasticity to slide over the underlying tissue in a way that mimicked normal penile skin, allowing comfortable erections.21PubMed. Reconstruction of penile skin loss using a combined therapy of negative pressure wound therapy, dermal regeneration template, and split-thickness skin graft application These results suggest that even after significant tissue destruction, functional and cosmetically acceptable outcomes are achievable without requiring complex free-flap surgery.
For men undergoing urethral reconstruction, a related concern is whether surgery itself might cause erectile problems. Research looking at erectile function scores before and after urethroplasty found no statistically significant change overall, though men whose stricture was located in the penile portion of the urethra did face a higher risk of postoperative penile curvature.22PubMed Central. Erectile dysfunction after urethroplasty
Why People Wait Too Long to Seek Help
Perhaps the most practically important thing to know about penile erosion is that many people delay seeking care far longer than they would for a similar problem anywhere else on their body. In a study of men with penile cancer, nearly two thirds waited more than six months before seeing a doctor, and the most commonly reported reason was embarrassment about symptoms in a sexual body area.23PubMed. Initial symptoms and delay in patients with penile carcinoma That delay did not necessarily correlate with more advanced disease at the time of diagnosis in that study, but the broader point stands: embarrassment is a poor reason to let a potentially serious condition go unexamined.
Erosions caused by herpes, lichen planus, or drug reactions are uncomfortable but manageable when treated promptly. Erosions caused by cancer are curable when caught at the surface stage but much harder to treat once they invade deeper tissue. And vascular emergencies like Fournier’s gangrene have mortality rates that climb steeply with each hour of delay. Whatever the cause, early evaluation by a dermatologist or urologist is the single most valuable step. A physical exam, possibly a biopsy, and appropriate lab work can almost always identify the cause and point toward effective treatment. The conversation may feel awkward, but it is routine for the clinician on the other side of it.