Morton's Neuroma A Morton's neuroma is a benign (noncancerous) swelling along a nerve in the foot that carries sensations from the toes. The reason the nerve starts to swell is unknown. Paronychia A paronychia is an infection of the skin that surrounds a toenail or fingernail. Gout Gout is a disorder characterized by too much uric acid in the blood and tissues. In gout, crystals of uric acid are deposited in the joints, where they cause a type of arthritis called gouty arthritis. Heel Pain Heel pain is a common symptom that has many possible causes. Fallen Arch A fallen arch or flatfoot is known medically as pes planus. The foot loses the gently curving arch that normally is on the inner side of the sole, just in front of the heel. Bunion A bunion is a firm, painful bump that forms over a bony prominence (bulge) at the base of the big toe. Plantar Fasciitis Plantar fasciitis is a painful inflammation of the plantar fascia, a fibrous band of tissue on the sole of the foot that helps to support the arch. Frostbite Frostbite is the freezing of body tissues as a result of extreme cold. Athlete's Foot (Tinea Pedis) Athlete's foot, also known as tinea pedis, is a common foot infection caused by fungi called dermatophytes. Corn and Callus Corns and calluses are both a thickening of the outer layer of skin.