Vulvar sores have dozens of possible causes, and the list extends well beyond sexually transmitted infections. Genital herpes, syphilis, skin conditions like lichen sclerosus, autoimmune diseases, medication reactions, friction injuries, and even responses to ordinary viral illnesses can all produce painful or painless lesions on the vulva. Figuring out what you’re dealing with usually requires a clinician’s evaluation, because many of these conditions look strikingly similar to each other on the surface.
Genital Herpes
Herpes simplex virus (HSV) is one of the most common causes of vulvar sores worldwide and the one many people think of first. The infection produces small blisters that break open into shallow, weeping ulcers. These sores typically begin to heal about 12 days after they first appear, and around 70% of people with symptoms during a first outbreak also experience fever, headache, or body aches alongside the genital lesions.1PubMed Central. Genital Herpes Simplex Virus (HSV) Infection During Pregnancy – Recommendations of the Working Group on Obstetrics and Prenatal Medicine (AGG – Section on Maternal Disorders) A first episode tends to be the most severe. Recurrences are usually milder and shorter, sometimes producing just a single sore or a patch of irritation that could easily be mistaken for something else.
People with weakened immune systems, including those living with HIV, face a higher risk of atypical herpes presentations. Instead of the classic clusters of small blisters, they can develop large, tumor-like, or thickened lesions that persist for weeks and resist standard treatment.2International Journal of Infectious Diseases. Hypertrophic genital herpes in an HIV-infected female patient: Imiquimod as an alternative treatment These unusual forms are one reason clinicians sometimes order lab testing even when the sore doesn’t look like “textbook” herpes.
Syphilis
Syphilis is a sneakier cause of vulvar sores because its hallmark lesion, called a chancre, is painless. The chancre appears at the site of infection within about 10 to 90 days after exposure and usually shows up as a single, firm, round ulcer. Because it doesn’t hurt and often resolves on its own within a few weeks, many people never notice it or assume it was nothing serious.3PubMed Central. Syphilis of the vulva That missed window is a problem: untreated syphilis progresses through secondary and latent stages that can eventually affect the heart, brain, and other organs.
The painlessness is the key distinguishing feature. If you discover a vulvar sore that doesn’t hurt, especially if you’ve had a new sexual partner, syphilis testing is important even if the sore seems to be going away.
Other Sexually Transmitted Infections
Beyond herpes and syphilis, a few less common STIs cause vulvar ulcers. Chancroid produces painful sores with ragged edges and a whitish base, and the nearby lymph nodes often swell and become tender. Donovanosis (also called granuloma inguinale) creates raised, beefy-red ulcers that bleed easily when touched.4Medicine. Tropical STIs Lymphogranuloma venereum, caused by certain strains of chlamydia, can also produce genital ulcers followed by swollen inguinal lymph nodes. These infections are more common in tropical regions, but with global travel they can show up anywhere.
Telling these infections apart by appearance alone is unreliable. Research on clinical diagnosis of genital ulcers found that accuracy varied widely depending on the condition. Even experienced clinicians correctly identified the cause of a genital ulcer less than two-thirds of the time for several of these infections.5PubMed Central. Genital ulcer disease: accuracy of clinical diagnosis and strategies to improve control in Durban, South Africa Lab testing is the only way to be certain.
Lipschütz Ulcers and Non-Sexually Acquired Genital Sores
Not every vulvar ulcer traces back to a sexually transmitted infection, and this is one of the most under-recognized facts about genital sores. Lipschütz ulcers are painful, sometimes dramatic-looking ulcers that appear suddenly on the vulva, often in adolescents and young women who have never been sexually active. They are thought to result from an immune reaction to an infection elsewhere in the body, such as Epstein-Barr virus, mycoplasma pneumonia, or even a garden-variety respiratory illness.6PubMed Central. When It’s Not a Sexually Transmitted Infection (STI): A Diagnostic Challenge of Severe Lipschütz Ulcer in a Young Woman Cases following SARS-CoV-2 infection and, rarely, COVID-19 vaccination have also been reported.7PubMed Central. Vulvar Aphthous Ulcers in Perimenarchal Adolescents after COVID-19 Vaccination: A Multicenter Case Series
The pattern is recognizable once you know about it: a young person develops flu-like symptoms, followed within days by deep, painful vulvar ulcers that look alarming but heal on their own within about two weeks. Most workups fail to identify a specific infectious or autoimmune cause, and the condition is considered self-limiting.8PubMed. Acute genital ulcers in nonsexually active young girls: case series, review of the literature, and evaluation and management recommendations The real challenge is that these ulcers can mimic herpes or autoimmune disease, which leads to unnecessary anxiety and invasive testing, particularly in teens who may feel accused of sexual activity they haven’t had.9PubMed. Lipschütz Ulcer in a 10-Year-Old Girl Following Pharyngotonsillitis: Case Report of a Rare Cause of Acute Genital Ulceration in Pediatrics
Treatment is focused on comfort: anti-inflammatory pain relievers, sitz baths, topical lidocaine for pain, and zinc oxide barrier cream to protect the raw skin.7PubMed Central. Vulvar Aphthous Ulcers in Perimenarchal Adolescents after COVID-19 Vaccination: A Multicenter Case Series If you or your child develops acute vulvar ulcers following a viral illness, it’s worth asking a provider about this diagnosis before assuming the worst.
Behçet’s Disease
Behçet’s disease is a chronic inflammatory condition that causes recurrent painful ulcers in the mouth and genitals, along with eye inflammation and skin problems. The genital ulcers can look a lot like herpes lesions but tend to be deeper, and they come back in unpredictable cycles. The disease is most common in people of Middle Eastern, East Asian, and Mediterranean descent, and it usually first appears in early adulthood.10PubMed Central. Fever, Leukocytosis, and Ulcerated Vulvar Lesions: An Atypical Presentation Concerning Behcet’s Disease
The clue that points toward Behçet’s is the combination of symptoms. A person with recurrent vulvar ulcers who also gets mouth sores, eye redness, or unusual skin lesions should bring up Behçet’s with their doctor. The condition doesn’t go away, but the flares can be managed with medications that tamp down the overactive immune response.11PubMed Central. Behçet’s disease, painful genital ulcerations and steroid pulse therapy
Chronic Skin Conditions
Several dermatologic conditions affect the vulva and can produce sores, fissures, or areas that break down. Lichen sclerosus is one of the more common culprits. It creates thin, white, wrinkled patches on the vulvar and perianal skin, sometimes in a figure-of-eight pattern around both areas. Over time the skin becomes fragile and prone to tearing, which means cracks and raw spots can appear from everyday activities or minor friction.12PubMed Central. Vulvar Lichen Sclerosus et Atrophicus The shrinking and thinning of tissue can make sex, urination, and even sitting uncomfortable.
Lichen sclerosus is often mistaken for a yeast infection or dismissed as normal aging, especially in postmenopausal women who make up a significant portion of cases. But it also occurs in younger women and even children. Diagnosis often requires a punch biopsy, which is a small tissue sample taken in a clinic. This procedure is underused despite being straightforward, and getting an accurate diagnosis early matters because long-standing untreated lichen sclerosus carries a small risk of vulvar cancer.13PubMed Central. Vulvar punch biopsy for evaluating vulvar dermatoses in primary care: Procedural guide
Vulvar Crohn’s Disease
Crohn’s disease is best known as a bowel condition, but it can affect the vulva even before any intestinal symptoms appear. Vulvar Crohn’s can show up as deep, knife-cut-shaped fissures, persistent swelling, redness, or ulcers on the labia. What makes this especially tricky is that in roughly 20% to 36% of cases, the vulvar symptoms precede the diagnosis of intestinal disease, either because the bowel symptoms haven’t started yet or because they’re mild enough to go unnoticed.14PubMed Central. Vulvar Crohn disease: Diagnostic challenges and approach to therapy
If you have persistent vulvar swelling or deep fissures that don’t respond to typical treatments, especially combined with any digestive symptoms like chronic diarrhea or abdominal cramping, it’s worth discussing the possibility of Crohn’s with your provider. A biopsy showing a particular type of inflammation called granulomas can help clinch the diagnosis.
Medication Reactions
Some medications cause a condition called fixed drug eruption, where the same spot on the body reacts every time you take the offending drug. On the vulva, this typically shows up as a raw, erosive sore that reappears in the same location with each exposure. Unlike fixed drug eruptions on other body parts, vulvar fixed drug eruptions tend to lack the dark pigmentation that usually makes the condition recognizable. They are often erosive, symmetrical on both sides, and nonspecific-looking on biopsy, which makes them easy to misdiagnose as herpes or another infection.15PubMed. Vulvar fixed drug eruption. A report of 13 cases
Common culprits include NSAIDs, antibiotics like sulfonamides, and even acetaminophen (paracetamol). One case report documented a chronic erosive vulvitis in an older woman that turned out to be a fixed drug eruption from regular paracetamol use.16PubMed. Vulval fixed drug eruption due to paracetamol The key clue is the recurring nature tied to medication use. If you notice that a vulvar sore keeps coming back and you’ve recently started a new medication, or if it flares up around the same time you take an over-the-counter painkiller, mention the connection to your doctor.
Friction, Pressure, and Ingrown Hairs
Sometimes the explanation is mechanical. Friction from tight clothing, vigorous exercise, or prolonged sitting can cause raw spots, folliculitis (infected hair follicles), or boils on the vulva. Cycling is a particularly well-documented source. In a study of female cyclists, 60% reported saddle sores including spots, boils, cysts, and ingrown hairs at points of contact with the saddle. Many described a progression from small irritations to larger, sometimes infected boils.17PubMed Central. Female cyclists’ experiences of saddle sores and their effect on cycling Pressure, friction, and sweat all contribute.
Ingrown hairs from shaving or waxing the bikini area are another extremely common cause of vulvar bumps that can become painful, red, and swollen enough to resemble an infection. These usually respond to warm compresses, gentle exfoliation, and keeping the area clean. If a bump doesn’t improve after a week or two, or if you develop a fever, it’s worth getting it checked to rule out a deeper abscess that needs drainage.
Yeast and Fungal Infections
Vulvovaginal candidiasis, the common yeast infection, doesn’t always stay inside the vaginal canal. Severe or recurrent cases can cause redness, swelling, and small cracks or erosions on the vulvar skin, especially in the labial folds. Researchers have pointed out that there are actually two distinct forms of genital candidiasis: the classic estrogen-dependent vaginal type and a cutaneous form that affects the vulvar skin itself, behaves differently, and may require different management approaches.18PubMed Central. Genital cutaneous candidiasis versus chronic recurrent vulvovaginal candidiasis: distinct diseases, different populations People with diabetes, those on immunosuppressive medications, and pregnant individuals are at higher risk for complicated yeast infections that spill onto the vulvar skin.
When a Sore That Won’t Heal Could Be Cancer
This is the possibility that worries people the most, and it does need to be mentioned even though it’s uncommon. Vulvar cancer, most often squamous cell carcinoma, can present as a persistent ulcer, a lump, or a sore that simply refuses to heal. A study of 80 women with squamous cell disease of the vulva found that about 14% had presented initially with a persistent vulvar ulcer as their main complaint. Most were postmenopausal, with a median age of 72. Concerning details emerged: more than half of the women who had an initial office biopsy received benign results, only for invasive cancer to be found on subsequent excision.19PubMed. The risk of squamous cell carcinoma in persistent vulvar ulcers
Vulvar cancer can also mimic other conditions. One case report described invasive squamous cell carcinoma that looked like a diabetic ulcer to the treating clinicians.20Clinical Research Trials. Invasive squamous cell carcinoma of the vulva clinically mimicking a diabetic ulcer: A potential diagnostic pitfall The takeaway is not that every vulvar sore is cancer. It is that any sore lasting longer than a few weeks, especially in an older adult, deserves a biopsy. A single negative biopsy doesn’t always rule out malignancy if the sore persists, because the initial sample might have missed the cancerous tissue.
Why Getting Diagnosed Can Be Difficult
One of the frustrating realities of vulvar sores is that many of these conditions look similar on the surface. A painful ulcer could be herpes, a Lipschütz ulcer, Behçet’s disease, or a drug reaction. A painless one might be syphilis, an early cancer, or a healing Crohn’s fissure. Visual inspection alone gets the wrong answer more often than you might expect, as research on clinical diagnosis accuracy has demonstrated across multiple types of genital ulcer disease.5PubMed Central. Genital ulcer disease: accuracy of clinical diagnosis and strategies to improve control in Durban, South Africa
Multiplex PCR testing, which screens a single swab for multiple pathogens at once, has improved the situation for infectious causes. One study using this approach on mucocutaneous ulcers found that about 45% tested positive for syphilis, 21% for herpes, and roughly 31% came back negative for all pathogens tested, meaning nearly a third of genital ulcers in that sample had a noninfectious explanation.21PubMed Central. Use of a Multiplex PCR Assay To Assess the Presence of Treponema pallidum in Mucocutaneous Ulcerations in Patients with Suspected Syphilis For non-infectious causes, a punch biopsy remains the gold standard. It is a quick office procedure and is particularly important for persistent, recurrent, or atypical-looking sores.13PubMed Central. Vulvar punch biopsy for evaluating vulvar dermatoses in primary care: Procedural guide
Barriers to Seeking Help
Many people delay seeing a doctor about vulvar sores because of embarrassment, fear of judgment, or worry about being stereotyped. Research on women with chronic vulvar pain found that half did not seek medical care at all, and among those who didn’t, about 40% cited a perception that doctors would stereotype them. Paradoxically, women who did seek care were even more likely to report feeling stigmatized by their providers.22PubMed Central. Perceived Stereotyping and Seeking Care for Chronic Vulvar Pain
This stigma is a genuine barrier to getting an accurate diagnosis. Many of the conditions described here are not sexually transmitted at all, and even those that are carry no moral weight. If a clinician’s manner makes you uncomfortable, it’s worth seeking a second opinion from a gynecologist or vulvar dermatology specialist. The consequences of delaying diagnosis range from prolonged discomfort for self-limiting conditions all the way to missed cancer or untreated syphilis progressing silently through your body. The discomfort of a visit is almost always outweighed by the relief of knowing what you’re dealing with and having a path to treatment.
What to Note Before Your Appointment
If you’re planning to see a clinician about a vulvar sore, a few details will help them narrow the possibilities faster:
- Timeline: When did you first notice it? Did it appear suddenly or develop gradually?
- Pain level: Painful sores point toward herpes, chancroid, Behçet’s, or Lipschütz ulcers. Painless ones raise suspicion for syphilis or, in older adults, cancer.
- Recurrence: Has this happened before in the same spot? That pattern fits herpes or fixed drug eruption.
- Other symptoms: Fever, body aches, mouth sores, joint pain, eye redness, digestive issues, or a recent respiratory illness can all provide diagnostic clues.
- Medications: Any new prescriptions, supplements, or even regular over-the-counter painkillers.
- Sexual history: New partners, type of contact, barrier use. Clinicians ask because it changes the testing strategy, not to pass judgment.
Photographs can also be useful if the sore changes quickly, since some lesions evolve from blisters to ulcers to scabs over just a few days and may look very different by the time you’re in the exam room. A clear photo from when symptoms were at their worst gives the clinician more information to work with.