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Differential diagnosis of acute scrotal pain
By FrcemStudyZone editorial Team
11 Jul, 2026

Differential diagnosis of acute scrotal pain

Differential diagnosis of acute scrotal pain

1. Torsion of the testicular appendage

Typical features include:

  •  More gradual onset than spermatic-cord torsion. 
  •  Localised upper-pole tenderness. 
  •  A tender paratesticular nodule. 
  •  Preserved cremasteric reflex. 
  •  Normal testicular lie. 
  •  Possible blue-dot sign. 
  •  Patient usually systemically well. 

The blue-dot sign is strongly supportive when present but is seen in only a minority of cases.

Where the diagnosis is certain, treatment is conservative with analgesia, anti-inflammatory medication, rest and scrotal support. Where uncertainty remains, the patient should be managed as possible testicular torsion and undergo urgent surgical review or exploration. 

2. Epididymitis or epididymo-orchitis

Features favouring infection include:

  •  Gradual onset over hours or days. 
  •  Dysuria or urinary frequency. 
  •  Urethral discharge. 
  •  Fever. 
  •  Epididymal tenderness. 
  •  Sexual exposure in an appropriate age group. 
  •  Recent urinary instrumentation or obstructive urinary symptoms in older adults. 

Investigations may include urinalysis, urine culture and testing for sexually transmitted infection according to age, history and local guidance.

Neither urinary symptoms nor an abnormal urinalysis safely excludes torsion. Prehn’s sign is also insufficiently reliable to determine management. 

3. Incarcerated inguinal hernia

Consider this where there is:

  •  A tender inguinoscrotal swelling. 
  •  Irreducibility. 
  •  Vomiting. 
  •  Abdominal distension. 
  •  Features of bowel obstruction. 
  •  A distressed infant or young child. 

This requires immediate surgical assessment. 

4. Fournier’s gangrene

Red flags include:

  •  Severe pain out of proportion to examination findings. 
  •  Rapid progression. 
  •  Skin discolouration. 
  •  Bullae. 
  •  Necrosis. 
  •  Crepitus. 
  •  Systemic toxicity. 
  •  Immunosuppression, diabetes or recent urinary instrumentation. 

Management requires immediate senior surgical involvement, resuscitation, broad-spectrum intravenous antibiotics and emergency debridement. Imaging must not delay theatre when the clinical diagnosis is evident. 

5. Testicular trauma

Trauma may cause:

  •  Contusion. 
  •  Haematoma. 
  •  Testicular rupture. 
  •  Dislocation. 
  •  Trauma-induced torsion. 

A history of trauma should not automatically exclude torsion, particularly where the severity of pain or examination findings appears disproportionate to the reported injury.

6. Testicular tumour

Although many tumours present as painless masses, malignancy may occasionally present with discomfort or acute pain.

A palpable intratesticular mass or a suspected alternative diagnosis that would substantially alter management is an appropriate indication for urgent ultrasound. 

7. Referred ureteric pain

A ureteric stone may produce ipsilateral groin or testicular discomfort. The testicular examination is usually normal.

Referred pain should only be accepted after serious scrotal pathology has been appropriately considered. 

Comparison of major diagnoses

Feature                                             Testicular torsion                                        Appendage torsion                                Epididymo-orchitis

Onset                                                  | Sudden                                               | Usually gradual                                | Usually gradual
Pain                                          | Severe, diffuse testicular                             | Localised upper pole                        | Epididymal or posterior
Nausea or vomiting                        | Common                                                 | Less common                                | Less typical
Testicular lie                                 | High or horizontal                                     | Usually normal                           | Usually normal
Cremasteric reflex                    | Often absent                                             | Usually present                                 | Usually present
Urinary symptoms                       | Usually absent                                           | Absent                                                 | May be present
Blue-dot sign                                | Absent                                                     | May be present                                         | Absent
Management                         | Urgent exploration                                            | Conservative if certain                       | Antimicrobials when indicated
Diagnostic uncertainty               | Explore                                                        | Treat as possible torsion                           | Torsion must still be excluded

High-yield Final FRCEM SBA decisions

Clinical scenario                                                                                                                                                 Best answer

Sudden pain, vomiting, hard high-riding testis, TWIST 6                                             | Immediate senior surgical referral and scrotal exploration
TWIST 2 but sudden severe pain and abnormal horizontal lie                                     | Urgent surgical review; torsion is not excluded
TWIST 3 with genuine uncertainty and immediate expert Doppler available              | Ultrasound may be used if it will not delay definitive treatment
Strong clinical suspicion but normal Doppler blood flow                                               | Urgent exploration
Recurrent self-resolving episodes with normal examination between attacks             | Suspect intermittent torsion and obtain urgent urological assessment
Localised upper-pole tenderness with a convincing blue-dot sign                                 | Conservative management if testicular torsion is confidently excluded
Lower abdominal pain and vomiting in a boy                                                                           | Examine the testes
Painful undescended testis                                                                                                         | Immediate surgical assessment for torsion
Pain improves after manual detorsion                                                                                                   | Continue to urgent exploration and definitive fixation
Pain has lasted more than 24 hours                                                                                      | Continue urgent surgical assessment; duration does not exclude salvage
Abnormal urinalysis with a high-riding tender testis                                                                  | Do not exclude torsion; obtain urgent surgical assessment
Normal cremasteric reflex but otherwise concerning presentation                                                  | Torsion remains possible

Common Final FRCEM traps

Trap 1: “A TWIST score of 0–2 excludes torsion”

Incorrect.

A low score reduces the probability but does not safely rule out torsion. Approximately 1 in 25 patients with confirmed torsion in the GIRFT evidence review had a score of 0–2. 

Trap 2: “A TWIST score of 3–4 should always be managed with ultrasound”

Incorrect.

Ultrasound may assist where there is genuine uncertainty, but persistent clinical concern requires urgent surgical management. A score of 0–4 does not exclude torsion.

Trap 3: “Every acute scrotum requires Doppler ultrasound”

Incorrect.

A clinically convincing torsion requires urgent exploration. Routine imaging may introduce a harmful delay. 

Trap 4: “Normal arterial flow excludes torsion”

Incorrect.

Early, partial and intermittent torsion may retain arterial flow. A negative scan does not overrule a concerning clinical presentation. 

Trap 5: “The testis is unsalvageable after six hours”

Incorrect.

Salvage becomes progressively less likely, but six hours is not an absolute cut-off. The degree of cord twisting also affects viability.

Trap 6: “Presentation after 24 hours no longer requires emergency referral”

Incorrect.

Late presentation still requires urgent surgical assessment. Some testes remain salvageable, and the diagnosis requires definitive management.

Trap 7: “Pain relief after manual detorsion means surgery is unnecessary”

Incorrect.

Residual torsion and retorsion remain possible. Exploration and fixation are still required. 

Trap 8: “Urinary symptoms establish epididymitis”

Incorrect.

Urinary symptoms support infection but do not independently exclude torsion. Clinical assessment remains essential.

Trap 9: “Prehn’s sign differentiates torsion from epididymitis”

Incorrect.

Relief of pain on testicular elevation is insufficiently reliable to determine management.

Trap 10: “A blue-dot sign always avoids surgery”

Incorrect.

It supports appendage torsion, but if there is diagnostic uncertainty between appendage torsion and spermatic-cord torsion, urgent exploration is safer. 

Final FRCEM examination summary

Remember the following five rules:

  1. Testicular torsion is a clinical and surgical emergency.
  2. TWIST 5–7 with less than 48 hours of pain supports urgent scrotal exploration.
  3. TWIST 0–4 does not exclude torsion.
  4. Ultrasound is an adjunct and must not delay surgery.
  5. A normal ultrasound does not exclude early, partial or intermittent torsion.

The single most important examination statement is:

When testicular torsion cannot be confidently excluded, arrange immediate senior surgical assessment and urgent scrotal exploration.

Frequently Asked Questions

What TWIST score requires scrotal exploration?

In the current GIRFT children and young people’s pathway, a TWIST score of 5–7 with less than 48 hours of continuous pain supports scrotal exploration unless a convincing alternative diagnosis would significantly alter management. 

Does a low TWIST score exclude testicular torsion?

No. A score of 0–4 does not exclude torsion. Persistent clinical concern requires urgent surgical assessment.

Should every patient with acute testicular pain undergo ultrasound?

No. Ultrasound is most useful where the diagnosis is uncertain, an important alternative diagnosis is suspected or continuous pain has been present for at least 48 hours. It must not significantly delay surgery.

Can Doppler ultrasound be normal in testicular torsion?

Yes. Early, partial or intermittent torsion may retain arterial flow. A normal scan does not completely exclude torsion. 

Is the cremasteric reflex always absent in torsion?

No. An absent reflex supports torsion, but its presence does not absolutely exclude the diagnosis.

Does pain lasting more than six hours mean the testis is lost?

No. The probability of salvage falls with time, but viability also depends on the degree of twisting. Urgent assessment and exploration remain necessary.

What should be done after successful manual detorsion?

The patient must still proceed to urgent surgical exploration and definitive orchidopexy because residual torsion or retorsion may occur.

Should a boy with abdominal pain have a testicular examination?

Yes. Testicular torsion may present predominantly as lower abdominal pain, nausea or vomiting, particularly in younger children. 

Key references

  • GIRFT Children and Young People: Testicular Torsion Pathway, Version 2.1, updated May 2026. 
  • British Association of Urological Surgeons: Testicular Torsion. 
  • British Association of Urological Surgeons: Acute Scrotal Pain. 
  • European Association of Urology: Paediatric Urology—Acute Scrotum.


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