# Situation: A public health nurse runs adolescent-friendly health services on weekend afternoons at a Rural Health Unit (RHU). Adolescents from the municipality come for counseling, immunization, and reproductive health services. A 17-year-old boy comes with his father, who consents to his treatment. He has had a painless genital ulcer for 2 weeks, and his syphilis infection has been confirmed per protocol. He has no penicillin allergy. The physician orders benzathine penicillin G 2.4 million units by deep intramuscular (IM) injection. Which plan for giving the drug and counseling him is CORRECT?

> source: MyMerci (mymerci.kr)  
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> subject: Nursing Practice I — Community Health Nursing

## 문제

Situation: A public health nurse runs adolescent-friendly health services on weekend afternoons at a Rural Health Unit (RHU). Adolescents from the municipality come for counseling, immunization, and reproductive health services.

A 17-year-old boy comes with his father, who consents to his treatment. He has had a painless genital ulcer for 2 weeks, and his syphilis infection has been confirmed per protocol. He has no penicillin allergy. The physician orders benzathine penicillin G 2.4 million units by deep intramuscular (IM) injection. Which plan for giving the drug and counseling him is CORRECT?

## 보기

1. Deep IM once; fever and aches within 24 hours are expected, not allergy **✔ 정답**
2. Deep IM weekly for 3 weeks; fever and aches within 24 hours are expected
3. Deep IM once; fever and aches within 24 hours signal a penicillin allergy
4. Deep IM weekly for 3 weeks; fever and aches within 24 hours signal allergy

**정답: 1**

## 해설

Two rules apply. A painless ulcer present for 2 weeks is a primary chancre, which is early syphilis, so benzathine penicillin G 2.4 million units is given deep intramuscularly (IM) once; the weekly dose for 3 weeks is for late latent syphilis or syphilis of unknown duration. Fever and aches within 24 hours are the Jarisch–Herxheimer reaction, which is expected and is not an allergy; the client is still observed for 15 to 30 minutes after injection with adrenaline (epinephrine) available.

## 심화 해설

Clinical context and staging

A painless genital ulcer that has been present for 2 weeks is the classic presentation of a primary syphilitic chancre. Because the lesion is still in the primary stage, this is classified as early syphilis. The correct treatment for early syphilis in an adolescent without penicillin allergy is benzathine penicillin G 2.4 million units given as a single deep intramuscular injection. The three-weekly-dose regimen is reserved for late latent syphilis or syphilis of unknown duration, not for a primary chancre of only two weeks’ duration [1][2].

The staging of syphilis determines both the dose and the number of injections, so recognizing the painless chancre as primary syphilis is the key to selecting the one-time regimen. A randomized trial comparing one dose with three weekly doses in early syphilis supports the use of a single injection in this population [2].

| Stage | Presentation | Benzathine penicillin G regimen |
| --- | --- | --- |
| Primary syphilis | Painless chancre, usually within 2–6 weeks after exposure | 2.4 million units IM once |
| Secondary syphilis | Rash, mucocutaneous lesions, lymphadenopathy | 2.4 million units IM once |
| Early latent syphilis | Asymptomatic, infection acquired within the previous year | 2.4 million units IM once |
| Late latent or unknown duration | Asymptomatic, duration greater than one year or unknown | 2.4 million units IM weekly for 3 weeks |

Jarisch–Herxheimer reaction versus penicillin allergy

Within the first 24 hours after the injection, the adolescent may develop fever, chills, myalgia, headache, or malaise. This constellation is the Jarisch–Herxheimer reaction, an expected immunologic response to the rapid killing of treponemes and release of inflammatory cytokines. It is not an allergic reaction and does not require discontinuation of penicillin [3].

Fever and body aches within 24 hours of benzathine penicillin G for early syphilis should be interpreted as the Jarisch–Herxheimer reaction, which is self-limited and expected, not as evidence of penicillin allergy. A secondary analysis of a randomized trial documented this reaction prospectively and confirmed that it occurs commonly after treatment of early syphilis with benzathine penicillin G [3].

Key point! A true penicillin allergy presents with urticaria, angioedema, bronchospasm, or anaphylaxis, typically within minutes to a few hours. The Jarisch–Herxheimer reaction is a febrile, flu-like syndrome that peaks around 6–12 hours and resolves spontaneously.

Nursing and safety considerations

Even though the Jarisch–Herxheimer reaction is expected, the adolescent should still be observed for 15 to 30 minutes after the intramuscular injection. Emergency equipment, including epinephrine, must be immediately available because anaphylaxis, although rare, can occur with any penicillin preparation [1]. The injection must be given deep into a large muscle mass, such as the dorsogluteal or ventrogluteal site, to reduce local pain and ensure proper absorption.

Watch out! Do not confuse observation for anaphylaxis with treatment of the Jarisch–Herxheimer reaction. Observation with epinephrine available is a universal safety measure for any injectable penicillin; the fever and aches themselves are managed supportively with fluids, rest, and antipyretics if needed.

Counseling points for the adolescent and father

The adolescent and his father should be informed that the single injection treats the infection, but serologic follow-up is required to confirm cure. The Jarisch–Herxheimer reaction may occur and is not a reason to stop treatment or to label the adolescent as penicillin-allergic. Partners within the appropriate look-back period must also be evaluated and treated to prevent reinfection [1]. In this RHU setting, the weekend adolescent-friendly service supports confidential, developmentally appropriate counseling while still involving the father as the consenting guardian.

The correct plan is a single deep IM injection of benzathine penicillin G 2.4 million units, with anticipatory guidance that fever and aches within 24 hours represent the expected Jarisch–Herxheimer reaction, not an allergy.References (research sources)

- [1]Sexually Transmitted Infections Treatment Guidelines, 2021.GuidelineWorkowski KA, Bachmann LH, Chan PA, Johnston CM, Muzny CA, Park I, Reno H, Zenilman JM, Bolan GA. (2021) · DOI: 10.15585/mmwr.rr7004a1

- [2]One Dose versus Three Doses of Benzathine Penicillin G in Early Syphilis.Research articleHook EW, Dionne JA, Workowski K, McNeil CJ, Taylor SN, Batteiger TA (2025) · DOI: 10.1056/NEJMoa2401802

- [3]Jarisch-Herxheimer Reaction After Benzathine Penicillin G Treatment in Adults With Early Syphilis: Secondary Analysis of a Randomized Clinical Trial.RCT/clinical trialDionne JA, Zhu C, Mejia-Galvis J, Workowski K, Batteiger TA, Dombrowski JC (2025) · DOI: 10.1001/jamanetworkopen.2024.59490

## 임상 시나리오

Early Syphilis in Adolescents: One-Dose IM TreatmentStaging drives regimen; post-dose reaction is expected, not allergy
A painless genital ulcer lasting 2 weeks is a primary chancre, classifying the infection as early syphilis. The correct regimen is benzathine penicillin G 2.4 million units given as a single deep intramuscular injection.

The weekly for 3 weeks schedule is reserved for late latent syphilis or syphilis of unknown duration, not for a primary chancre of only two weeks.

Fever and aches within 24 hours after injection indicate the Jarisch–Herxheimer reaction, an expected response to treatment. It is not a penicillin allergy.

CautionObserve the adolescent for 15–30 minutes after injection with epinephrine (adrenaline) available, even though the Jarisch–Herxheimer reaction is expected and not an allergic response.

## 핵심 개념

- **Primary syphilis** — Early stage marked by a painless chancre, typically appearing 2-6 weeks after exposure.
- **Benzathine penicillin G** — Long-acting intramuscular antibiotic; 2.4 million units once for early syphilis.
- **Jarisch-Herxheimer reaction** — Expected febrile reaction with aches within 24 hours of treatment, not an allergic response.
- **Late latent syphilis** — Asymptomatic infection of over one year or unknown duration, requiring three weekly injections.
- **Chancre** — Painless genital ulcer characteristic of primary syphilis.

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