What is the recommended treatment for a patient with chlamydia and gonorrhea who has an anaphylactic reaction to penicillin (PCN) and a rash with azithromycin (Zithromax)?

Treatment for Chlamydia and Gonorrhea with Penicillin Anaphylaxis and Azithromycin Rash

For a patient with anaphylactic penicillin allergy and azithromycin rash, treat gonorrhea with ceftriaxone 500 mg IM once (cephalosporins have <3% cross-reactivity with penicillin in true IgE-mediated allergy) and chlamydia with doxycycline 100 mg orally twice daily for 7 days.

Gonorrhea Treatment Approach

Ceftriaxone remains the treatment of choice despite penicillin allergy. True anaphylactic reactions to penicillin result in only 1-3% cross-reactivity with cephalosporins, making ceftriaxone 500 mg IM a safe and effective option 1. The 2021 CDC guidelines recommend 500 mg ceftriaxone intramuscularly once for uncomplicated gonorrhea at all anatomic sites 1.

Alternative for Cephalosporin-Intolerant Patients

If the patient cannot tolerate any cephalosporin (which is rare even with documented penicillin anaphylaxis):

• Spectinomycin 2 g IM single dose is the only recommended alternative, with 98.2% efficacy for urogenital and anorectal infections 2
• Critical limitation: Spectinomycin is only 52% effective against pharyngeal gonorrhea, so pharyngeal culture follow-up at 3-5 days is mandatory if pharyngeal exposure occurred 2
• Important caveat: Spectinomycin availability is limited in the United States; check CDC resources for current availability 2

What NOT to Use for Gonorrhea

• Fluoroquinolones are NOT recommended due to widespread resistance 1
• Azithromycin 2 g monotherapy has insufficient efficacy (only 93% cure rate) and causes severe GI distress in 35% of patients 2, 3
• No oral alternatives exist for pharyngeal gonorrhea in cephalosporin-allergic patients 1

Chlamydia Treatment Approach

Doxycycline 100 mg orally twice daily for 7 days is the definitive treatment when azithromycin cannot be used 2, 4, 5.

Why Doxycycline is Optimal

• 98% microbial cure rate for chlamydial infections 4, 5, 6
• Lower cost than azithromycin with extensive safety data 2, 5
• No cross-reactivity with macrolides (azithromycin) or penicillins 7

Alternative Chlamydia Regimens (in descending order of preference)

If doxycycline is contraindicated (pregnancy, age <8 years):

1. Levofloxacin 500 mg orally once daily for 7 days - 88-94% efficacy, but reserve for patients who cannot use doxycycline 4, 6
2. Ofloxacin 300 mg orally twice daily for 7 days - similar efficacy to doxycycline but more expensive 2
3. Erythromycin base 500 mg orally four times daily for 7 days - less desirable due to poor GI tolerance and compliance issues 2, 4, 6

Critical Management Steps

Medication Administration

• Dispense medications on-site and directly observe the first dose of doxycycline to maximize compliance 2, 4
• Administer doxycycline with adequate fluids and food/milk to reduce esophageal irritation risk 7

Sexual Abstinence Requirements

• Abstain from all sexual intercourse for 7 days after initiating treatment AND until all sex partners complete treatment 4, 5, 6
• Failure to treat partners leads to reinfection in up to 20% of cases 5

Partner Management

• All sex partners from the preceding 60 days must be evaluated, tested, and empirically treated for both gonorrhea and chlamydia 2, 4, 5
• Treat the most recent partner even if last sexual contact was >60 days before diagnosis 2, 4

Follow-Up Testing

• No test-of-cure needed if patient completes doxycycline and is asymptomatic 4, 5, 6
• Mandatory retest at 3 months for all patients due to reinfection rates up to 39% in some populations 4, 5, 6
• Do not test before 3 weeks post-treatment - nucleic acid tests yield false-positives from dead organisms 5, 6

Additional STI Screening

• Test for syphilis and HIV at initial visit, as all patients with new STD diagnoses require comprehensive screening 2

Common Pitfalls to Avoid

• Do not assume cephalosporin allergy based solely on penicillin history - true cross-reactivity is <3% with IgE-mediated reactions 1
• Do not use fluoroquinolones for gonorrhea - resistance rates make them ineffective 1
• Do not skip pharyngeal culture follow-up if using spectinomycin, as it fails in 48% of pharyngeal infections 2
• Do not allow sexual activity before partner treatment completion - both patient and all partners must finish treatment 4, 5
• Do not interpret recurrent infection as treatment failure - 84-92% of recurrences are reinfections from untreated partners 5