Bunions. Each of these fluid-filled pads covers the joint of the big toe. The majority of bunions are caused by the condition hallux valgus, in which the big toe (hallux) bends inwards and the base of the joint protrudes, as here. The continued rubbing of the joint on tight shoes leads to inflammation and bunions. Bunions can be very painful and they will increase in size unless correctly-fitting shoes are worn. Shoes which force the big toe into a straight position will help relieve small bunions, but larger ones may require surgery to correct the shape of the joint.