After performing oral sex, a 47-year-old man developed a wound inside his mouth, according to a new case study by a team of dentists from Mexico.

The report titled "Fellatio-associated erythema of the soft palate: an incidental finding during a routine dental evaluation" was published in BMJ Case Reports on June 11.

The unnamed patient from Mexico did not experience any symptoms as the wound was only noticed during a dental check-up at the School of Dentistry at the Universidad de Montemorelos, Nuevo Leon. 

The dentists identified fellatio as the cause after the patient informed them that he was sexually active with men and had last performed oral sex three days before the dental appointment. Fellatio is a method of oral sex when a person uses their mouth to stimulate the genital or anal area of their sexual partner.

The patient also reported a history of marijuana and cocaine use. The authors emphasized the importance of obtaining a comprehensive history and a detailed oral examination to avoid misdiagnosis.

"The contact of the palate with the penile glands may cause a hematoma due to blunt trauma and dilatation of the blood vessels because of the negative pressure created while sucking," stated Dr. Luis Alberto Mendez, who treated the patient. "With this information, we concluded that the erythema on the soft palate was associated with the practice of oral sex."

The wound was circle-shaped, reddened, and located on the roof of his mouth. In medical terms, the reddened skin is referred to as erythema. While the wound reported in the study is relatively rare, the authors noted that a previous study of 132 sex workers in Peru found that 17 of the participants suffered lesions in the mouth due to oral sex.

"Oral sex is a very common sexual practice, and as clinicians, we should consider it as a potential cause of palatal lesions in our differential diagnosis," the authors stated. According to the Centers for Disease Control and Prevention (CDC), nearly 85 percent of sexually active adults (aged 18 to 44 years) reported having oral sex at least once with a partner of the opposite sex.

The patient was advised to refrain from performing oral sex until the wound healed. A reduction in redness was noticed one week later followed by the wound completely healing two weeks later.

The authors revealed that if the healing had not occurred, an examination may have been required as such a wound could potentially be a sign of oral tumors. They added that the possibility of sexually transmitted disease should be considered among high-risk patients.

To ensure safety, avoid fellatio or cunnilingus (oral stimulation of the vagina) if you have mouth ulcers or sores. Using a dental dam, which is a latex or polyurethane sheet, can also prevent the spread of infections.