Infectious Disease High-Yield: STIs, Pneumonia, UTI, and More for FNP Boards

Clinical High-Yield · 12 min read · April 28, 2026

Infectious disease is one of the most consistently tested sections on the FNP boards, and it rewards a specific kind of preparation: knowing the classic presentation, the causative organism, and the first-line antibiotic. The boards are not testing your ability to manage sepsis in the ICU. They are testing whether you can match a clinical presentation to the right treatment in a primary care setting.

Sexually Transmitted Infections: The Complete Board Review

Chlamydia: The most common bacterial STI in the United States. Often asymptomatic. When symptomatic: urethral discharge (men), cervicitis, pelvic inflammatory disease (women). Diagnosis: NAAT (nucleic acid amplification test) from urine or swab. Treatment: azithromycin 1g PO single dose OR doxycycline 100mg BID × 7 days. Treat partners. Screen all sexually active women ≤25 years annually (USPSTF recommendation).

Gonorrhea: Caused by Neisseria gonorrhoeae. Presentation: purulent urethral discharge (men), cervicitis, PID (women), pharyngitis, proctitis. Diagnosis: NAAT. Treatment: ceftriaxone 500mg IM single dose (or 1g if weight ≥150kg). Due to increasing resistance, dual therapy with azithromycin is no longer recommended by current CDC guidelines — ceftriaxone alone is now preferred. Treat partners. Co-test for chlamydia.

Syphilis: Caused by Treponema pallidum. The stages and their presentations are high-yield:

  • Primary: painless chancre (single, indurated, clean-based ulcer) at the site of inoculation
  • Secondary: diffuse maculopapular rash including palms and soles, condyloma lata, mucous patches, flu-like symptoms
  • Latent: asymptomatic (early latent <1 year, late latent >1 year)
  • Tertiary: gummas, cardiovascular syphilis (aortitis), neurosyphilis

Diagnosis: non-treponemal tests (RPR, VDRL) for screening, confirmed with treponemal tests (FTA-ABS, TP-PA). Treatment: benzathine penicillin G IM (single dose for primary/secondary, 3 weekly doses for latent/tertiary). Penicillin allergy: doxycycline for non-pregnant patients; desensitization and penicillin for pregnant patients (no alternative is proven safe in pregnancy).

Herpes Simplex Virus (HSV): HSV-1 (oral) and HSV-2 (genital) — though either can affect either site. Presentation: painful vesicles that ulcerate, dysuria, lymphadenopathy. Diagnosis: clinical; confirmed by viral culture or PCR from lesion. Treatment: acyclovir, valacyclovir, or famciclovir. Suppressive therapy reduces recurrences and transmission risk.

Trichomonas: Caused by Trichomonas vaginalis (a protozoan). Women: frothy, yellow-green vaginal discharge, strawberry cervix, vulvar pruritus. Men: often asymptomatic. Diagnosis: NAAT (most sensitive) or wet prep (motile trichomonads). Treatment: metronidazole 2g PO single dose (or 500mg BID × 7 days). Treat partners.

Board Pearl: The boards love to test the "which STI causes a painless ulcer?" question. The answer is syphilis (primary chancre). Painful genital ulcers: herpes (most common...