Differential Diagnosis for Finger Infection with Swelling Beyond Joint Line
- Single Most Likely Diagnosis
- Paronychia with extension: This is the most likely diagnosis because paronychia is a common infection of the finger that can spread beyond the joint line if not properly treated. It typically starts around the nail and can extend to the surrounding tissues.
- Other Likely Diagnoses
- Felon: A felon is an infection of the fingertip pulp, which can cause swelling and may extend beyond the joint line. It's a common condition that requires prompt treatment to avoid complications.
- Herpetic whitlow: This is a viral infection caused by herpes simplex virus, leading to painful lesions and swelling on the finger, which can extend beyond the joint line.
- Cellulitis: This is a bacterial infection of the skin and subcutaneous tissues that can cause swelling, redness, and warmth, potentially extending beyond the joint line if the infection spreads.
- Do Not Miss Diagnoses
- Osteomyelitis: Although less common, osteomyelitis (bone infection) is a serious condition that can result from an untreated or inadequately treated finger infection. It requires prompt diagnosis and treatment to prevent long-term damage.
- Septic arthritis: If the infection spreads to the joint, it can cause septic arthritis, a condition that requires immediate medical attention to prevent joint destruction and long-term disability.
- Necrotizing fasciitis: This is a rare but life-threatening condition where the infection spreads rapidly through the fascia, causing necrosis of the tissue. Early recognition and treatment are crucial for survival.
- Rare Diagnoses
- Erysipelas: A type of bacterial infection that affects the upper dermis, causing well-demarcated, raised, and indurated lesions, which can occur on the fingers and potentially extend beyond the joint line.
- Sporotrichosis: A fungal infection caused by Sporothrix schenckii, typically acquired through skin prick injury from a thorn or other vegetation, which can cause lesions and swelling on the finger.
- Mycobacterial infections: Certain mycobacteria can cause infections of the skin and soft tissues, including the fingers, which might present with swelling beyond the joint line, although this is relatively rare.