Mouth ulcers are common, often resulting from minor trauma or stress, but their appearance can sometimes signal a sexually transmitted infection (STI). Certain bacterial and viral infections transmitted through sexual contact can manifest as lesions in and around the mouth. While most oral sores are benign and heal quickly, persistent, unusually painful, or systemic symptoms warrant professional medical consultation. Only a healthcare professional can provide an accurate diagnosis.
Sexually Transmitted Infections That Cause Oral Ulcers
Several STIs cause lesions or ulcers in the oral cavity, primarily Syphilis, the Herpes Simplex Virus (HSV), and Human Immunodeficiency Virus (HIV). These pathogens cause ulcers that vary significantly in appearance, duration, and associated pain.
Syphilis, caused by Treponema pallidum, produces a characteristic primary stage ulcer called a chancre at the site of entry (lips, tongue, or pharynx). Secondary syphilis can cause highly infectious, raised white or grayish patches known as mucous patches.
HSV (typically type 1 or 2) causes painful, recurring oral lesions, often called cold sores. These start as small, fluid-filled blisters that quickly rupture into shallow ulcers. The virus remains dormant and can reactivate periodically.
HIV infection does not cause a unique ulcer, but immune system compromise leads to various oral manifestations. People living with HIV are susceptible to severe and persistent forms of other oral conditions, including unusually large or slow-healing ulcers related to opportunistic infections.
Identifying the Characteristics of STD Related Sores
The primary syphilitic chancre is a firm, round, and relatively painless ulceration. It has a clean, indurated base and usually appears as a single lesion, often on the lips, tongue, palate, or tonsillar areas. The ulcer heals on its own within three to eight weeks, even without treatment, but the infection remains in the body.
Herpetic lesions are almost always painful and present as clustered, small, fluid-filled vesicles on a reddened base. These blisters rupture quickly to form shallow, yellowish-gray ulcers that eventually crust over. An outbreak is often preceded by a tingling or burning sensation (prodrome), and the sores resolve within seven to ten days.
Ulcers associated with advanced HIV disease are persistent, deep, or refractory to standard treatments. The compromised immune function allows common oral sores, like canker sores, to become severe and debilitating. These painful sores can take weeks to heal, differing significantly from the course in an individual with a healthy immune system.
Distinguishing STD Ulcers from Common Mouth Lesions
Differentiating an STI-related ulcer from a common mouth lesion requires observing several key clinical characteristics. Aphthous ulcers, or canker sores, are the most frequent non-STI oral lesion, appearing solitary with a white or yellowish center and a bright red, inflamed border.
Canker sores are highly painful, contrasting significantly with the often painless syphilitic chancre. They are found on movable soft tissues like the cheeks, lips, or floor of the mouth, and unlike herpes, they are not preceded by a tingling sensation and are not contagious.
Traumatic ulcers result from accidental cheek biting, dental appliances, or thermal burns. The cause is usually obvious, and these ulcers heal rapidly once the source of injury is removed. They lack the clustered appearance of herpes and the firm, indurated base of a chancre.
The key differentiators are pain and duration. Common traumatic and aphthous ulcers are acutely painful and heal spontaneously within 7 to 14 days. STI-related lesions, especially the chancre, may be painless but signal a systemic infection requiring specific medical intervention.
Diagnosis and Management of Oral STIs
Any unexplained or persistent mouth ulcer should be evaluated by a healthcare provider. Diagnosis begins with a physical examination and review of the patient’s history, though laboratory testing is necessary for a definitive diagnosis. The appearance and location of the lesion often guide the initial suspicion.
Syphilis diagnosis involves blood tests detecting antibodies to Treponema pallidum. A swab from the ulcer may also be used for dark-field microscopy or PCR testing to identify the bacteria. Herpes is often diagnosed clinically, but confirmation involves swabbing the base of a blister for viral culture or PCR.
Management depends on the specific pathogen. Syphilis is curable and treated with antibiotics, typically penicillin, which eliminates the bacteria. Herpes outbreaks are managed with oral antiviral medications like acyclovir to reduce severity and frequency. HIV management involves antiretroviral therapy (ART), which suppresses the virus and helps the immune system control opportunistic infections and severe ulcers.