Could I have contracted a sexually transmitted infection (STI) given my sudden onset of low libido, erectile dysfunction (ED), yellow and watery semen, and testicular atrophy without testicular pain?

Your Symptoms Are Unlikely to Be an STI—This Pattern Suggests Hormonal Dysfunction

Your constellation of symptoms—low libido, erectile dysfunction, testicular atrophy, and altered semen—strongly suggests hypogonadism (low testosterone) rather than a sexually transmitted infection. 1, 2

Why This Is Probably Not an STI

STIs typically cause localized symptoms that you don't have:

• Gonorrhea and chlamydia cause urethral discharge, burning with urination, and testicular pain—not testicular shrinkage or low libido 3
• Epididymitis (the most common STI-related testicular condition in men under 35) presents with unilateral testicular pain and swelling, which you explicitly don't have 3
• Yellow semen and low volume can occur with genitourinary infections, but these do not cause testicular atrophy or the hormonal changes that lead to erectile dysfunction and low libido 2

What Your Symptoms Actually Indicate

Your specific combination points to hormonal disruption:

• Testicular atrophy results from hormonal problems (hypogonadism), chronic liver disease, or primary testicular failure—not infection 2
• Low libido plus erectile dysfunction plus testicular shrinkage is the classic triad of hypogonadism 1
• The absence of testicular pain makes infection highly unlikely 3

Immediate Testing You Need

Get these blood tests done in the morning (testosterone levels fluctuate throughout the day):

1. Total testosterone on two separate mornings—diagnosis requires persistent low levels 1
2. FSH (follicle-stimulating hormone)—distinguishes primary testicular failure (elevated FSH) from pituitary/brain problems (low/normal FSH) 1
3. Prolactin—elevated prolactin directly suppresses libido and causes erectile dysfunction independent of testosterone levels 1
4. LH (luteinizing hormone)—helps distinguish primary from secondary hypogonadism 2

If testosterone is borderline, also check SHBG (sex hormone-binding globulin), since elevated SHBG reduces bioavailable testosterone and can cause symptoms despite "normal" total testosterone 1

Critical Next Steps Based on Results

If prolactin is elevated: You need a pituitary MRI to evaluate for prolactinoma or other pituitary masses 1

If testosterone is low with low/normal FSH (secondary hypogonadism): This indicates hypothalamic-pituitary dysfunction and is potentially reversible—review all medications for drugs that suppress hormones (opiates, steroids, glucocorticoids) 1

If testosterone is low with elevated FSH (primary hypogonadism): This indicates testicular failure itself 1

Semen Analysis Is Also Essential

Get a complete semen analysis to assess volume, pH, sperm count, and white blood cells 2. This will:

• Confirm whether the yellow color and low volume represent infection (pyospermia—white blood cells in semen) or other causes 2
• Evaluate fertility status 4
• Rule out ejaculatory duct obstruction (presents with acidic semen pH <7.0, volume <1.4 mL) 1

Common Pitfalls to Avoid

• Don't start testosterone replacement if you want to preserve fertility—it suppresses sperm production and can cause complete absence of sperm 1, 2
• Don't assume normal testosterone rules out problems—if total testosterone is borderline, check SHBG and calculate free testosterone 1, 5
• A history of decreased libido and testicular atrophy cannot predict whether you have hypogonadism—you must measure hormones directly 5

Addressing Modifiable Factors

While awaiting test results:

• Obesity decreases testosterone and worsens erectile function—weight loss improves both 1
• Smoking is associated with reduced fertility and erectile dysfunction—cessation is recommended 1
• Review all medications and supplements, especially anabolic steroids, which cause exactly this symptom pattern 1

If Liver Disease Is Suspected

If you have risk factors (alcohol use, hepatitis exposure), check liver enzymes, bilirubin, albumin, and coagulation studies, as chronic liver disease causes testicular atrophy and hormonal dysfunction 2