Differential Diagnosis for Swelling and Bruising on Dorsum of Foot
Single Most Likely Diagnosis
- Morton's Neuroma or Metatarsalgia: Given the location of the swelling and bruising on the dorsum of the foot over the second metatarsal and pain on the plantar surface of the metatarsal heads, this diagnosis is highly plausible. Morton's Neuroma involves a nerve compression between the metatarsal bones, leading to pain and sometimes swelling, while metatarsalgia refers to a general pain in the metatarsal region, which could be due to various reasons including poor foot mechanics or overuse.
Other Likely Diagnoses
- Stress Fracture: Although there's no pain on palpation today, stress fractures can present with swelling and bruising, especially if the fracture is in the early stages or not fully developed. The second metatarsal is a common site for stress fractures due to its role in weight-bearing activities.
- Metatarsal Phalangeal Joint Sprain: A sprain in this area could lead to swelling, bruising, and pain, especially if the injury is recent. The lack of pain on palpation today might indicate a resolving sprain.
- Bursitis: Inflammation of the bursae around the metatarsal heads or the joints of the foot could cause swelling, bruising, and pain, particularly on the plantar surface.
Do Not Miss Diagnoses
- Osteomyelitis or Septic Arthritis: Although less likely, infections such as osteomyelitis (bone infection) or septic arthritis (joint infection) can present with swelling, bruising, and pain. These conditions are medical emergencies requiring prompt treatment to prevent serious complications.
- Deep Vein Thrombosis (DVT): While DVT typically presents in the calf, it's conceivable for it to occur in the foot, especially if there's a history of recent immobilization, surgery, or cancer. Swelling and bruising could be part of the presentation.
Rare Diagnoses
- Erythromelalgia: A rare disorder characterized by burning pain, heat, and redness in the hands and feet. It could potentially cause swelling and might be considered if other diagnoses are ruled out.
- Gout or Pseudogout: Although more commonly associated with the big toe, these conditions can affect other joints, including those in the foot. They could present with acute swelling, bruising, and pain, especially if a flare occurs.
- Neoplastic Conditions: Rarely, swelling and bruising could be signs of a tumor, either benign or malignant, affecting the bones or soft tissues of the foot.