A visible bunion can easily become the assumed explanation for any pain near the big toe. However, the prominence may be incidental, and treating it will not necessarily resolve symptoms arising from another structure.
Big-toe joint arthritis can cause deep joint pain, stiffness and discomfort during push-off. Gout may present with sudden, intense pain, swelling, heat and redness. Infection can also cause redness and swelling and requires prompt assessment, particularly if there is a wound or systemic illness.
A superficial bursa can become inflamed where footwear rubs over the prominence. Local cutaneous nerve irritation may produce burning, tingling or sensitivity rather than mechanical joint pain. Pain beneath the first metatarsal head may arise from the sesamoid bones, their surrounding tissues or a stress injury.
Other forefoot problems may coexist with the bunion. These include second metatarsophalangeal joint synovitis, plantar plate injury, Morton’s neuroma, hammertoe deformity and transfer metatarsalgia. The patient may point to the bunion even though the most limiting pain is actually under the second metatarsal or between the toes.
The pattern of symptoms, physical examination and weight-bearing X-rays often clarify the cause. Blood tests, ultrasound, MRI or other investigations are used selectively when the clinical picture suggests another diagnosis.
Identifying the pain generator is particularly important before surgery. Correcting a bunion for pain that actually arises from gout, neuropathy or advanced joint arthritis may not achieve the expected benefit.