Differential Diagnosis for a Suspected Ingrown Nail

When considering the diagnosis of an ingrown nail, it's crucial to differentiate it from other conditions that may present similarly. The following categories help organize the potential diagnoses:

• Single Most Likely Diagnosis
  • Ingrown nail (onychocryptosis): This condition occurs when the nail grows into the surrounding skin, leading to pain, swelling, and sometimes infection. It's the most common diagnosis for the symptoms described, given the direct involvement of the nail and its immediate surroundings.
• Other Likely Diagnoses
  • Paronychia: An infection of the skin around the nail, which can be acute or chronic. It presents with redness, swelling, and sometimes pus, similar to an ingrown nail but is more related to bacterial or fungal infections.
  • Nail fungus (onychomycosis): While it primarily affects the nail itself, causing discoloration, thickening, and brittleness, it can lead to conditions that increase the risk of an ingrown nail or mimic its symptoms.
  • Traumatic nail injury: Direct trauma to the nail or the area around it can cause symptoms similar to an ingrown nail, including pain and swelling.
• Do Not Miss Diagnoses
  • Osteomyelitis: A bone infection that can occur in the bone beneath the nail. It's a serious condition that requires prompt treatment to prevent long-term damage.
  • Cellulitis: A bacterial skin infection that can spread rapidly and become severe. It may start around the nail area and can be mistaken for a simple ingrown nail or paronychia.
  • Squamous cell carcinoma or other nail bed tumors: Although rare, these can mimic the appearance of an ingrown nail, especially if they cause the nail to become elevated or if there's associated inflammation.
• Rare Diagnoses
  • Erythromelalgia: A disorder that causes burning pain, heat, and redness in the hands and feet, which could potentially be confused with the pain and redness of an ingrown nail.
  • Psoriatic nail disease: Part of psoriasis, a chronic skin condition, which can affect the nails and surrounding skin, potentially mimicking some symptoms of an ingrown nail.
  • Glomus tumor: A rare, benign tumor that can occur under the nail, causing pain and sensitivity, which might be mistaken for an ingrown nail.

Each of these diagnoses has distinct features that can help in differentiating them from an ingrown nail. A thorough clinical examination and, when necessary, additional diagnostic tests are crucial for an accurate diagnosis and appropriate treatment.