| Necrotizing fasciitis (Fournier's gangrene) | Testicular torsion | Acute epididymitis | Torsion of appendix testis |
Historical features |
Onset of pain | Usually sudden | Usually sudden | Usually gradual | Usually sudden |
Duration of pain | Usually <12 hours | Usually <12 hours | Usually >24 hours | Usually >12 hours |
Previous pain episodes | No | Common | Occasional | Unusual |
Nausea and vomiting | Unusual | Common | Unusual | Occasional |
Fever | Common | Unusual | Common | Unusual |
History of trauma | Unusual | Occasional | Unusual | Unusual |
Dysuria or discharge | Rare | Unusual | Common | Unusual |
Physical findings |
Distinguishing features on examination | Tense edema of the skin, blisters/bullae, crepitus, subcutaneous gas | Horizontal lie, high-riding testis, bell clapper deformity, profound testicular swelling | None | Palpable nodule or "blue dot sign" |
Tenderness | Diffuse, rapidly progressive | Testicular initially, then diffuse | Epididymis initially, then diffuse | Anterosuperior pole of the testis initially, then diffuse |
Scrotal erythema or edema | Common, rapidly progressive | Common >12 hours | Common >12 hours | Common >12 hours |
Cremasteric reflex | Usually present | Usually absent | Usually present | Usually present |
Laboratory tests |
Pyuria | No | Unusual | Common | Unusual |
Positive smear, culture, rapid molecular testing, or NAAT for STI | No | No | Common | No |
Leukocytosis | Common | Uncommon | Common | Uncommon |