In a young male patient with burning during urination and low-grade fever, what is the likely diagnosis if he has a history of a recent unprotected encounter?

In this scenario, the symptoms of burning during urination and low-grade fever, combined with the history of a recent unprotected encounter, strongly suggest a diagnosis of prostatitis. Prostatitis, particularly in young males, is often associated with sexually transmitted infections, making the recent unprotected encounter a significant risk factor.

Burning during urination can indicate inflammation of the urethra or prostate, and the presence of low-grade fever suggests an inflammatory process, which aligns with acute prostatitis. The condition can be caused by bacterial infections, including those from sexually transmitted pathogens, especially in younger males.

While other options may also present with similar urinary symptoms, the combination of the patient’s age, the recent sexual history, and the specific symptoms point more towards prostatitis as the most likely diagnosis. Conditions like a chlamydia infection could cause similar symptoms but would typically present more prominently with discharge or might initially be asymptomatic. A urinary tract infection or cystitis usually affects females more frequently and would not typically be associated with fever as a primary symptom in young males without risk factors. Thus, the context of recent sexual activity along with the specific symptoms supports prostatitis as the appropriate diagnosis.