A discharge from the penis — especially if it is yellow, green, or accompanied by burning urination — is almost always an STI or urinary infection. This page tells you the causes, the tests, and why treating without testing leads to recurring infections.
Penile discharge has a narrow differential — most cases are gonorrhoea, chlamydia, or urethritis from other organisms. The colour, timing, and associated symptoms give clues; a urethral swab and NAAT test confirm.
Yellow or green, thick, purulent discharge — usually appearing 2–7 days after exposure. Often with burning urination. Very common STI. Treated with a single dose of ceftriaxone.
Clear or white, watery discharge — often mild or intermittent. Sometimes only noticed in the morning. Common STI; requires doxycycline 7–14 days.
Discharge with urethritis not caused by gonorrhoea — Mycoplasma, Ureaplasma, or Trichomonas. NAAT testing identifies the organism.
A frothy, sometimes itchy discharge — Trichomonas vaginalis infection. Treated with metronidazole.
Less common in men — discharge may accompany urethral irritation from ascending infection. Urine culture required.
Redness, swelling, and discharge from the glans — often from candida (thrush) or non-infectious causes. Topical antifungal or steroid cream treats it.
Urethral Swab / First-Catch Urine NAAT — NAAT for chlamydia and gonorrhoea — the most accurate test. First-catch urine (the first 10 mL of urination) is collected. Results in 24–48 hours.
Gram Stain of Discharge (Same-Day) — Gram-negative diplococci on gram stain of urethral discharge = gonorrhoea. A rapid presumptive result guiding immediate treatment.
Full STI Screen — HIV, syphilis, hepatitis B — a full sexual health screen alongside swabs.
Urine Culture — If UTI is suspected — identifies the causative organism and antibiotic sensitivity.
Taking antibiotics before the swab can make the test negative even when an infection is present. Get the test first — treatment follows the same day if indicated.
Until the infection is identified and treated — and for 7 days after treatment is completed — to prevent transmission.
STIs require partner notification and treatment. Both partners must be treated simultaneously to prevent re-infection.
Most STI clinics in Lagos see by appointment patients. Mascot Healthcare provides confidential STI assessment without judgment.
Book online or via WhatsApp — same-day assessment, transparent pricing, 4.9★ rated.