Differential Diagnosis for Ingrown Toenail
Single Most Likely Diagnosis
- Ingrown Toenail (Onychocryptosis): This is the most likely diagnosis given the patient's symptoms of a red, swollen, and ingrown toenail on the lateral side of the left big toe. The condition occurs when the nail grows into the surrounding skin, causing irritation, pain, and swelling.
Other Likely Diagnoses
- Paronychia: An infection of the skin around the nail, which could present with similar symptoms of redness and swelling. It's often caused by bacterial infection and can be acute or chronic.
- Cellulitis: A bacterial skin infection that can cause redness, swelling, and warmth in the affected area. While it's more widespread than paronychia, it could be considered if the infection has spread beyond the nail area.
- Contact Dermatitis: An allergic reaction or irritation caused by substances coming into contact with the skin, which could potentially cause redness and swelling around the toenail area if, for example, a new soap or lotion is used.
Do Not Miss Diagnoses
- Osteomyelitis: A bone infection that, although rare, could present with symptoms similar to an ingrown toenail if the infection has spread to the bone. It's crucial to consider this diagnosis, especially if the patient has a history of diabetes or other conditions that increase the risk of osteomyelitis.
- Deep Vein Thrombosis (DVT): While less common in the context of an ingrown toenail, DVT could cause swelling and redness in the leg. It's a critical diagnosis not to miss due to its potential for severe complications, such as pulmonary embolism.
- Diabetic Foot Ulcer: In patients with diabetes, what appears to be an ingrown toenail could actually be a foot ulcer, which requires immediate attention to prevent further complications.
Rare Diagnoses
- Malignant Melanoma: A rare type of skin cancer that could, in very rare instances, present in the nail area, causing changes that might be mistaken for an ingrown toenail.
- Squamous Cell Carcinoma: Another type of skin cancer that could potentially occur in the nail bed or surrounding skin, though it's exceedingly rare in this context.
- Erythromelalgia: A disorder that causes burning pain, heat, and redness in the hands and feet, which might be considered if the patient's symptoms do not respond to typical treatments for an ingrown toenail.