Differential Diagnosis for Middle Finger Swelling with Infected Nail
- Single most likely diagnosis
- Paronychia: This is the most likely diagnosis given the symptoms of nail infection, redness, and swelling around the nail of the middle finger. Paronychia is an infection of the skin around the nail and is commonly caused by bacterial infection, often due to Staphylococcus aureus.
- Other Likely diagnoses
- Felon: An infection of the fingertip pulp, which could present with swelling, redness, and sometimes pus. The symptoms can be similar to paronychia but typically involve the pad of the finger.
- Herpetic whitlow: A viral infection caused by herpes simplex virus, leading to painful, swollen, and sometimes pus-filled blisters on the finger. It's less common than bacterial infections but should be considered, especially if there's a history of herpes exposure.
- Onychomycosis (fungal nail infection): While this condition is more chronic and might not fully explain the acute swelling, it could be a contributing factor to the nail's susceptibility to infection.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Osteomyelitis: Bone infection, which could be a complication of untreated or severe paronychia or felon. It's crucial to diagnose and treat promptly to avoid serious complications.
- Septic arthritis: If the infection spreads to the joint, it could lead to septic arthritis, a condition that requires immediate medical attention to preserve joint function.
- Necrotizing fasciitis: A rare but life-threatening infection that could start with symptoms similar to paronychia or felon but rapidly progresses. Early recognition is critical for survival.
- Rare diagnoses
- Erysipelas: A type of skin infection that can cause redness and swelling, typically affecting the upper dermis, and is often accompanied by systemic symptoms like fever.
- Melanonychia: A condition characterized by a black or brown streak in the nail, which could be mistaken for an infection but is actually due to melanin deposition. It's not typically associated with swelling or redness but could be considered in the differential for nail changes.