Calluses are hyperkeratoses of the skin. This is a thickening of the surface layer of the skin, usually in response to pressure or friction. Calluses usually form on the ball of the foot, the heel, and the underside of the big toe (hallux). They may, however, form over any bony prominence. Calluses may be simple thickening of the skin. Sometimes they have a deep seated "core", known as a nucleation. This type of callus can be exquisitely painful to pressure, and is known to the podiatrist as an Intractable Plantar Keratosis.

• A hard growth usually on the ball of the foot
• Pain on weight bearing, relieved by rest
• Increased discomfort in thin soled and high heeled shoes
• More common in women than men

• High heeled shoes
• Malalignment of the metatarsal bones
• Abnormalities of gait
• Flat feet and High arched feet
• Excessively long metatarsal bone
• Obesity
• Bony prominence
• Loss (atrophy) of fat pad on the underside of the foot
• Short Achilles tendon

• Avoid high heeled shoes
• Buy shoes with a good arch and shock absorbing rubber sole
• Use an insole which absorbs shear forces inside the shoe (eg. Spenco® or Sorbothane®)
• Keep skin moist and supple with regular application of a moisturizer
• Use a pumice stone or other abrasive to reduce the thickness of the callus
• Apply non-medicated pads around the callus to relieve pressure
• Apply moleskin over areas that tend to callus

• Provide temporary relief by debriding (pare down) the callus and any deep seated core it may have. 
• Apply various pads to relieve pressure
• Recommend appropriate shoes
• Prescribe orthotics to correct functional problems and/or redistribute weight.
• Surgically realign metatarsals, or remove bony prominences

• Bursitis - the formation of a painful inflamed fluid-filled sac beneath the callus
• Discomfort of the back, hips, knees, legs, or feet due to changes in posture and/or gait due to pain.
• Development of an ulcer. An open area that forms within the callus. This may even extend down to bone.
• Infection of the soft tissues or bone.
• Diabetics and those with diminished circulation or sensation should always seek professional help.

• Verruca (warts)
• Various tumors of the skin and subcutaneous (below the skin) tissues
• Reaction to a foreign body (e.g. sliver or animal hair)
• Genetic or metabolic disorders of the skin, and some drug reactions.