Differential Diagnosis for a Loud and Continuous Crying Infant with Firm Hot Tender Bluish Inguinal Mass

• Single Most Likely Diagnosis
  • Irreducible Inguinal Hernia: This condition is highly likely given the description of a firm, hot, tender, and bluish inguinal mass. An irreducible inguinal hernia, especially if it has become incarcerated or strangulated, can cause severe pain and the described physical findings, leading to continuous crying in an infant.
• Other Likely Diagnoses
  • Testicular Torsion: Although less common in infants, testicular torsion can present with a firm, tender, and possibly bluish mass if the torsion is severe and compromises blood flow. The pain from testicular torsion can cause significant distress, leading to continuous crying.
• Do Not Miss Diagnoses
  • Appendiceal Torsion: Although rare and less likely given the inguinal location of the mass, appendiceal torsion or any condition involving the appendix that could cause an inguinal mass (e.g., an appendiceal stump appendicitis in a child with a history of appendectomy) is critical not to miss due to the potential for severe complications if not promptly treated.
• Rare Diagnoses
  • Other rare conditions such as a varicocele, hydrocele, or a soft tissue tumor could potentially present with a mass, but these are less likely to cause the acute, severe symptoms described. Additionally, conditions like meconium peritonitis or omphalitis with extension could theoretically cause abdominal and inguinal symptoms but would be less likely to present as a localized inguinal mass without other significant findings.

Each of these diagnoses requires careful consideration of the clinical presentation, history, and physical examination findings, along with appropriate diagnostic imaging and laboratory tests to confirm the diagnosis and guide management.