A hydrocele is an abnormal collection of serous fluid between the parietal and visceral layers of the tunica vaginalis surrounding the testis. [1] It is the most common cause of painless scrotal swelling in adult males, with an estimated incidence of ~1% in the adult male population. [2] Hydroceles are classified as primary (idiopathic) or secondary (due to infection, trauma, neoplasm, or surgery). [1][3]
The following algorithm from the AAFP provides a systematic approach to evaluating scrotal masses, including hydrocele:
1. History
- Onset and duration of scrotal swelling — gradual vs. sudden
- Unilateral vs. bilateral; fluctuation in size throughout the day (suggests communicating hydrocele with patent processus vaginalis) [4]
- Pain or discomfort — typically painless; large hydroceles may cause heaviness or dull ache [3]
- History of trauma, recent surgery (especially varicocelectomy, hernia repair), or infection (epididymitis, orchitis) [2][4]
- Travel history to endemic areas for lymphatic filariasis (sub-Saharan Africa, South/Southeast Asia, Pacific Islands) [5-6]
- Constitutional symptoms: fever, weight loss, night sweats (raise concern for malignancy or infection)
- Urinary symptoms: dysuria, hematuria, urethral discharge [3]
2. Alarm Features
- Acute scrotal pain — must rule out testicular torsion (surgical emergency; salvage rate ~90% within 6 hours) [3]
- Rapid onset of swelling with nausea/vomiting, high-riding testis, absent cremasteric reflex → torsion until proven otherwise [3]
- Hard, non-transilluminating, fixed intratesticular mass → suspect testicular malignancy [3][7]
- Non-reducible, tender inguinal/scrotal mass with abdominal pain → incarcerated/strangulated inguinal hernia [7-8]
- New-onset hydrocele in an adult with no clear etiology → warrants ultrasound to exclude underlying testicular tumor [3-4]
- Fever, erythema, and tenderness → infected hydrocele or epididymo-orchitis
3. Medications
- No medications are directly causative of hydrocele formation. However, hydrocele is a recognized complication following:
- Varicocelectomy (especially non-artery-sparing or non-microsurgical techniques) [4]
- Inguinal/scrotal surgery
- Treatment medications:
- NSAIDs (ibuprofen 400–600 mg PO q6–8h) for symptomatic discomfort
- Doxycycline (200–400 mg) used as sclerosant agent in aspiration and sclerotherapy [9-10]
- In filarial hydrocele: doxycycline 200 mg/day × 6 weeks (targets Wolbachia endosymbiont) followed by ivermectin + albendazole [11]
- Anticoagulants — not contraindicated but increase bleeding risk with aspiration or surgery [12]
4. Diet
- No specific dietary triggers or recommendations for idiopathic hydrocele
- Adequate hydration is generally advised perioperatively
- In filarial-endemic regions, mosquito bite prevention is more relevant than dietary modification
5. Review of Systems
- GU: dysuria, hematuria, urethral discharge, infertility concerns, erectile dysfunction
- GI: abdominal pain, nausea/vomiting (hernia, torsion), inguinal bulge with straining
- Constitutional: fever, weight loss, night sweats (malignancy, TB, filariasis)
- MSK: groin/inguinal pain, heaviness
- Dermatologic: scrotal skin changes, erythema, edema
6. Collateral History and Family History
- Family history of hydrocele (reported in ~4% of fathers and ~8% of brothers of affected patients) [13]
- Family history of inguinal hernia or cryptorchidism
- History of prematurity (congenital hydrocele more common in premature infants — 32.5% vs. 15.9%) [13]
- Social/occupational history: heavy lifting (may exacerbate communicating hydrocele), travel to filariasis-endemic areas [5]
7. Risk Factors
- Age: bimodal — neonates/infants (patent processus vaginalis) and older adults (idiopathic)
- Prematurity [13]
- Prior inguinal/scrotal surgery (especially varicocelectomy) [4]
- Epididymitis/orchitis or scrotal trauma [2]
- Lymphatic filariasis (Wuchereria bancrofti) — the most common cause worldwide, affecting ~25 million men [5-6]
- Testicular neoplasm (reactive hydrocele) [3]
- Peritoneal dialysis, ascites, VP shunt (communicating hydrocele in adults)
8. Differential Diagnosis
9. Past Medical History
- Prior episodes of hydrocele or scrotal swelling
- History of inguinal hernia repair, varicocelectomy, or other scrotal surgery [4]
- Epididymitis, orchitis, or STIs
- Cryptorchidism
- Renal transplant (hydrocele is a recognized complication) [15]
- Peritoneal dialysis or VP shunt
- Filariasis exposure or treatment
10. Physical Exam
- Inspection: scrotal asymmetry, skin changes, erythema
- Palpation:
- Smooth, fluctuant, non-tender, extratesticular mass [3]
- Testis may be difficult to palpate separately if hydrocele is large
- Palpate inguinal canal for hernia
- Check for spermatic cord thickening
- Transillumination: positive — fluid-filled hydrocele transmits light (key bedside test) [3]
- Cremasteric reflex: should be intact (absence suggests torsion) [3]
- Prehn sign: pain relief with testicular elevation suggests epididymitis, not typically relevant in painless hydrocele [3]
- Valsalva maneuver: communicating hydrocele may increase in size; varicocele will engorge [3]
- Examine standing and supine — communicating hydrocele may reduce when supine
11. Lab Studies
- Routine labs are generally not indicated for simple, painless hydrocele [3]
- If infection suspected: urinalysis, urine culture, GC/chlamydia NAAT
- If malignancy suspected: AFP, β-hCG, LDH (testicular tumor markers)
- If filariasis suspected: peripheral blood smear for microfilariae (nocturnal), filarial antigen testing [16]
- CBC if systemic infection is a concern
12. Imaging
- Scrotal ultrasound with Doppler — imaging modality of choice [3][17]
- Confirms diagnosis: anechoic fluid collection surrounding the testis
- Classifies type (simple vs. complex/septated)
- Critically important to exclude underlying testicular mass not palpable due to hydrocele [3-4][18]
- Doppler assesses testicular perfusion (rules out torsion)
- Ultrasound is nearly 100% sensitive for intrascrotal mass detection and 98–100% accurate for distinguishing intratesticular from extratesticular processes [17]
- When to order ultrasound:
- New-onset hydrocele in adults (to rule out underlying neoplasm) [4]
- Testis not palpable through the hydrocele [3]
- Any diagnostic uncertainty
- Painful or rapidly enlarging hydrocele
- CT/MRI rarely needed; may be considered if retroperitoneal pathology or abdominoscrotal hydrocele suspected
13. Special Tests
- Transillumination — simple bedside test; positive in hydrocele (fluid transmits light), negative in solid masses or hematocele [3]
- TWIST score (Testicular Workup for Ischemia and Suspected Torsion) — use if acute painful scrotum to risk-stratify for torsion [3]
- Point-of-care ultrasound (POCUS) — increasingly used in ED to rapidly differentiate hydrocele from other scrotal pathology
- Aspiration with fluid analysis: straw-colored, serous fluid in simple hydrocele; bloody fluid suggests trauma or malignancy; purulent fluid suggests infection
14. ECG
- Not routinely indicated for hydrocele
- Obtain if preoperative assessment is needed for hydrocelectomy in patients with cardiac risk factors
15. Assessment
Hydrocele is a benign condition that is typically idiopathic in adults and results from an imbalance of fluid secretion and reabsorption by the tunica vaginalis. [1] The clinical priority is to exclude dangerous underlying pathology — particularly testicular malignancy, inguinal hernia, and torsion. [3][7]
- Congenital (communicating): patent processus vaginalis; size fluctuates; most resolve by age 1–2 years [3][13]
- Acquired (non-communicating): idiopathic or secondary; does not fluctuate; more common in adults [2]
- Reactive hydrocele: secondary to epididymitis, orchitis, torsion, or tumor — treat the underlying cause [1]
- Complications: cosmetic concern, discomfort, rarely testicular compression affecting growth in children [19]
16. Treatment Plan
Conservative management
- Asymptomatic, simple hydroceles require no treatment — observation and reassurance [3]
- Scrotal support and NSAIDs for mild discomfort
- In infants, observe for at least 12–24 months as ~89% resolve spontaneously [13][20]
Aspiration and sclerotherapy
- Reasonable option for patients who prefer to avoid surgery or are poor surgical candidates [9-10]
- Technique: aspiration followed by instillation of doxycycline 200–400 mg as sclerosant
- Success rate: 77–84% with a single treatment [9-10]
- Higher recurrence rate than surgery; lower complication rate, lower cost, faster recovery [2]
- Best for simple, non-septated hydroceles [10]
Hydrocelectomy (definitive treatment)
- Indicated for symptomatic, large, or communicating hydroceles [1][3]
- Techniques: Jaboulay (eversion), Lord (plication), or excision
- Recurrence rate: 0.3–5% depending on technique [21]
- Complications: hematoma, infection, chronic pain, recurrence (~18% postoperative complication rate) [12]
- Office-based minimal-incision fenestration under local anesthesia is an option for patients unfit for general anesthesia [12]
Pediatric communicating hydrocele
17. Disposition
- Discharge from ED: vast majority of simple hydroceles — this is an outpatient condition [3]
- Urology referral (outpatient):
- Symptomatic hydrocele
- Communicating hydrocele
- New-onset hydrocele in adults (after ultrasound excludes malignancy)
- Persistent pediatric hydrocele beyond 12–24 months [3][13]
- Urgent/emergent consultation:
- Suspected testicular torsion → immediate urology consult [3]
- Incarcerated inguinal hernia → emergent surgical consultation [7]
- Suspected testicular malignancy → urgent urology referral [3]
- Admission criteria: essentially none for isolated hydrocele; admit only if concurrent surgical emergency (torsion, strangulated hernia)
18. Follow Up / Return Precautions
- Follow-up timing: outpatient urology within 2–4 weeks for symptomatic or new-onset adult hydroceles
- Pediatric: follow-up every 3–6 months to monitor for spontaneous resolution [13][22]
- Post-hydrocelectomy: follow-up at 1–2 weeks for wound check, then as needed
Return precautions — advise patients to seek immediate care for:
- Acute onset of severe scrotal pain (concern for torsion)
- Rapid increase in swelling, redness, or warmth (infection, hematocele)
- Fever or systemic illness
- Non-reducible inguinal bulge with pain (incarcerated hernia)
- New hard, painless testicular lump
Expected course: Simple idiopathic hydroceles are benign and may remain stable for years. Post-surgical recurrence is uncommon (<5% with complete excision). [21] Aspiration alone without sclerotherapy has a high recurrence rate and is generally not recommended as definitive treatment. [2]
References
1. A Review of Classification, Diagnosis, and Management of Hydrocele. — Hoang VT, Van HAT, Hoang TH, Nguyen TTT, Trinh CT. Journal of Ultrasound in Medicine : Official Journal of the American Institute of Ultrasound in Medicine. 2024.
2. Aspiration and Sclerotherapy Versus Hydrocoelectomy for Treating Hydrocoeles. — Shakiba B, Heidari K, Jamali A, Afshar K. The Cochrane Database of Systematic Reviews. 2014.
3. Scrotal Masses. — Langan RC, Puente MEE. American Family Physician. 2022.
4. Management of Hydrocele in Adolescent Patients. — Cimador M, Castagnetti M, De Grazia E. Nature Reviews. Urology. 2010.
5. Exploring Determinants of Hydrocele Surgery Coverage Related to Lymphatic Filariasis in Nepal: An Implementation Research Study. — Lama Yonzon C, Padmawati RS, Subedi RK, et al. PloS One. 2021.
6. Lymphatic Filariasis and Onchocerciasis. — Taylor MJ, Hoerauf A, Bockarie M. Lancet. 2010.
7. Evaluation of Scrotal Masses. — Crawford P, Crop JA. American Family Physician. 2014.
8. Inguinal Hernias: Diagnosis and Management. — Shakil A, Aparicio K, Barta E, Munez K. American Family Physician. 2020.
9. Aspiration and Sclerotherapy: A Minimally Invasive Treatment for Hydroceles and Spermatoceles. — Brockman S, Roadman D, Bajic P, Levine LA. Urology. 2022.
10. Aspiration and Sclerotherapy: A Nonsurgical Treatment Option for Hydroceles. — Francis JJ, Levine LA. The Journal of Urology. 2013.
11. Reduction in Levels of Plasma Vascular Endothelial Growth Factor-a and Improvement in Hydrocele Patients by Targeting Endosymbiotic Wolbachia Sp. In Wuchereria Bancrofti With Doxycycline. — Debrah AY, Mand S, Marfo-Debrekyei Y, et al. The American Journal of Tropical Medicine and Hygiene. 2009.
12. Office-Based, Minimal-Incision Modified Fenestration Technique for Symptomatic Hydroceles Under Local Anesthesia. — Ziegelmann M, Dodge N, Alom M, et al. Urology. 2020.
13. Natural History and Conservative Treatment Outcomes for Hydroceles: A Retrospective Review of One Center's Experience. — Acer-Demir T, Ekenci BY, Özer D, et al. Urology. 2018.
14. Differential Diagnosis of Acute Scrotum in Childhood And Adolescence With High-Resolution Duplex Sonography. — Deeg KH. Ultraschall in Der Medizin. 2021.
15. Tetracycline Sclerotherapy for Testicular Hydroceles in Renal Transplant Recipients. — Shokeir AA, Eraky I, Hassan N, et al. Urology. 1994.
16. Clinical, Parasitologic, and Immunologic Observations of Patients With Hydrocele and Elephantiasis in an Area With Endemic Lymphatic Filariasis. — Addiss DG, Dimock KA, Eberhard ML, Lammie PJ. The Journal of Infectious Diseases. 1995.
17. ACR Appropriateness Criteria® Newly Diagnosed Palpable Scrotal Abnormality. — Khatri G, Bhosale PR, Robbins JB, et al. Journal of the American College of Radiology : JACR. 2022.
18. Incidental Testicular Pathologies in Patients With Idiopathic Hydrocele Testis: Is Preoperative Scrotal Ultrasound Justified?. — Kafka M, Strohhacker K, Aigner F, et al. Anticancer Research. 2020.
19. Comparison of the Size of Bilateral Testis in Children With Unilateral Non-Communicating Hydrocele and Its Correlation With Age. — Li P, Liu F, Huang Y. PloS One. 2023.
20. Decision Making in the Management of Hydroceles in Infants and Children. — Naji H, Ingolfsson I, Isacson D, Svensson JF. European Journal of Pediatrics. 2012.
21. A Mechanism for Chronic Filarial Hydrocele With Implications for Its Surgical Repair. — Norões J, Dreyer G. PLoS Neglected Tropical Diseases. 2010.
22. Trends in Treatment Outcomes of Hydrocele in Japanese Children: A Single-Institute Experience. — Hori S, Aoki K, Ichikawa K, et al. International Journal of Urology : Official Journal of the Japanese Urological Association. 2020.