Differential Diagnosis
The patient's presentation of joint pain, discoloration on the toenails and middle fingers, subungual hyperkeratosis, and pitting nails suggests an underlying inflammatory or autoimmune condition. Here's a categorized differential diagnosis:
- Single most likely diagnosis
- B) Psoriasis: The presence of pitting nails and subungual hyperkeratosis are classic signs of psoriatic nail disease, which is often associated with psoriatic arthritis, explaining the joint pain. Psoriasis is a common condition that fits well with the described symptoms.
- Other Likely diagnoses
- A) Lichen planus: While lichen planus can cause nail changes, including thinning and ridging of the nails, it less commonly presents with the specific combination of pitting and subungual hyperkeratosis as seen in psoriasis. However, it remains a consideration, especially if there are other systemic or mucocutaneous manifestations of lichen planus.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- None are immediately apparent from the symptoms provided, but conditions like systemic lupus erythematosus (SLE) or sarcoidosis could potentially present with joint pain and nail changes, albeit less commonly. These conditions have significant implications for patient management and prognosis, making them important not to miss.
- Rare diagnoses
- Reiter's syndrome (reactive arthritis): This condition can present with joint pain and nail changes, among other symptoms, following a bacterial infection. It's less common than psoriasis but could be considered in the differential, especially if there's a history of recent infection.
- Sjögren's syndrome: An autoimmune disorder that can cause joint pain and has been associated with nail changes, though this is less common. It's more typically known for causing dry eyes and mouth.
Each of these diagnoses has a different set of implications for treatment and management, making a thorough diagnostic workup crucial for determining the best course of action for the patient.