Genital Ulcers: STI vs Non-STI Causes

What Are Genital Ulcers?

Genital ulcers do not always indicate a sexually transmitted infection. They may occur due to irritation, skin conditions, friction, allergic reactions, or infections in some cases. If your symptoms present more as fluid-filled bumps rather than open sores, our guide on blisters on the genitals may be more relevant. Because many conditions can produce similar-looking sores, the appearance of an ulcer alone cannot confirm the cause. STI testing may help provide clarity when there has been potential exposure or when symptoms persist.

Possible causes of genital ulcers may include:

Skin irritation or friction
Allergic or contact dermatitis
Inflammatory skin conditions
Herpes simplex virus
Syphilis
Other infections in some cases
Trauma from shaving or grooming

Symptoms alone cannot confirm whether a genital ulcer is caused by an STI.

Common Non-STI Causes of Genital Ulcers

Contact Dermatitis and Allergic Reactions

The genital skin is particularly sensitive. Soaps, shower gels, detergents, latex condoms, lubricants, and intimate hygiene products can all trigger allergic or irritant contact dermatitis.

Friction and Trauma

Physical friction from tight clothing, vigorous exercise, or sexual activity can cause small tears or abrasions in the genital skin that may develop into ulcer-like sores.

Shaving and Grooming

Shaving, waxing, or trimming the pubic area can result in ingrown hairs, folliculitis, or small cuts that may become inflamed and resemble ulcers.

Inflammatory Skin Conditions

Conditions such as lichen planus, lichen sclerosus, Behçet's disease, and psoriasis can all affect the genital area and produce ulcers or erosions.

Aphthous Ulcers

Similar to mouth ulcers, aphthous ulcers can occasionally occur on the genitals. They tend to be painful, shallow, and round, and they typically heal without treatment.

Blocked Glands and Cysts

Bartholin's cysts (in women) or sebaceous cysts can develop in the genital area. If these become inflamed or infected, they may rupture and leave an open sore.

STIs That May Cause Genital Ulcers

Herpes Simplex Virus (HSV)

Genital herpes, caused by HSV-1 or HSV-2, is one of the more common STI-related causes of genital ulcers. It typically presents as clusters of small, painful blisters that break open to form shallow ulcers. Our article on what herpes looks like provides a more detailed overview of how herpes symptoms can vary.

Syphilis

Primary syphilis characteristically produces a single, firm, painless ulcer known as a chancre. This typically appears at the site of infection 10 to 90 days after exposure. Because the chancre is painless and heals on its own within a few weeks, it can easily go unnoticed — which is why syphilis is one of the most commonly missed STIs.

Chancroid

Chancroid is a bacterial infection caused by *Haemophilus ducreyi*. It produces painful genital ulcers and may be accompanied by swollen lymph nodes.

Lymphogranuloma Venereum (LGV)

LGV is caused by specific strains of *Chlamydia trachomatis* and can produce genital ulcers alongside inguinal lymph node swelling.

How STI Symptoms Can Overlap With Other Conditions

A painless syphilis chancre may resemble an aphthous ulcer or a healing friction injury. Herpes blisters may be confused with contact dermatitis or folliculitis. An inflamed cyst may look similar to a chancroid lesion.

This overlap is precisely why visual assessment alone is insufficient. For a broader overview of how infections may present, see our guide to the most common STI symptoms in men and women. Testing remains the most reliable method of determining the cause.

When STI Testing May Be Sensible

There are several scenarios in which pursuing STI testing may be a prudent step:

Symptoms persist beyond a few days or worsen over time
A new sexual partner has been involved recently
Unprotected sexual contact has occurred
A partner has been diagnosed with an STI
Symptoms are recurring without a clear explanation
Multiple ulcers or additional symptoms such as discharge, pain during urination, or swollen lymph nodes are present

A full STI screen can test for multiple infections simultaneously, offering broader reassurance.

Frequently Asked Questions

Can a genital ulcer be normal?

In many cases, genital ulcers have benign causes such as friction, irritation, or minor skin conditions. However, because some STIs can also cause ulcers, testing may be advisable when there has been potential exposure.

Does a genital ulcer always mean I have an STI?

No. Genital ulcers can result from a wide range of causes, many of which are not related to sexually transmitted infections.

Should I get tested if the ulcer heals on its own?

In some cases, STI-related ulcers — such as syphilis chancres — heal without treatment while the underlying infection remains. If there has been a potential exposure, testing may still be sensible even after symptoms resolve.

When to Seek Medical Advice

Seek medical advice if you experience:

Severe or worsening pain
Ulcers that do not heal within two weeks
Fever or general feeling of being unwell
Swollen lymph nodes in the groin
Spreading rash or multiple new lesions

If you are concerned about a genital ulcer or possible STI exposure, confidential STI testing appointments are available at our UK clinic. Book a confidential appointment at a time that suits you.

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Disclaimer: This article is for general informational purposes only and does not constitute medical advice, diagnosis, or treatment. The information provided is not a substitute for professional clinical judgement. Sexual health concerns should be assessed on an individual basis by a qualified healthcare professional. If you are experiencing persistent, severe, or worsening symptoms, please consult an appropriate healthcare service. Our clinic provides private STI testing services only — we do not prescribe medication, provide ongoing treatment, or offer GP services.

Written: 7 March 2026 | Next Review Due: 7 March 2027