Adventitial Bursitis at the Fifth Metatarsal

Unlike a bursa that is normally present near a joint, an adventitial bursa develops in soft tissue exposed to repeated friction or load. It may create a tender, soft swelling beneath or beside the base or head of the fifth metatarsal, the long bone leading toward the little toe.

A narrow shoe, prominent bone, altered foot mechanics, or repeated side loading can concentrate pressure over the outer border. The irritated tissue can thicken and fill with fluid, making closed footwear or standing uncomfortable. Callus may sit over the same pressure point.

Similar-looking pain can come from a stress injury, fracture, bunionette, cyst, inflamed joint, tendon problem, gout, or infection. Examination focuses on the precise location, whether the lump moves or compresses, skin condition, footwear pattern, and pain with bone loading. Imaging is sometimes needed when the diagnosis is uncertain.

Temporarily reduce activities that repeatedly load the sore edge of the foot. Choose shoes with a wide toe box, a soft upper, secure fastening, and enough depth for padding. A podiatrist may adjust insoles or use an off-loading pad positioned around, rather than directly on, the tender area.

Protect intact skin and check it regularly, especially if diabetes, reduced sensation, or poor circulation is present. Medication or a cortisone injection may be considered after diagnosis, but pressure correction remains important. Do not puncture or drain a lump yourself; this can introduce infection and the swelling may not be a bursa.

Arrange prompt care if the area becomes red, hot, rapidly larger, begins draining, or is accompanied by fever. People with diabetes, poor circulation, reduced immunity, or loss of foot sensation should obtain early assessment for any broken skin, blister, or new swelling.

Seek urgent evaluation after an injury if you cannot bear weight, the foot looks deformed, or pain is severe and focused over bone. Persistent night pain, unexplained numbness, colour change, or a lump that is firm or continues to enlarge also warrants an in-person examination.

Useful questions include whether the tenderness is centred on a bursa, bone, tendon, or joint; whether imaging is appropriate; and which footwear feature is driving pressure. If an injection or aspiration is proposed, clarify the expected benefit, infection precautions, aftercare, and how the area will be off-loaded afterward.