Calluses and Corns
Calluses and Corns
Kathleen Weber
Basics
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Calluses and corns are common skin conditions.
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They result from increased pressure or friction; typically located on the hands and feet.
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A callus is an adaptive response to repetitive friction.
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Calluses and corns may lead to considerable discomfort and pain.
Description
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A callus is a plaque of hyperkeratosis of relatively even thickness caused by repetitive friction, pressure, or trauma, and commonly occurs over bony prominences (1).
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A corn is a localized, tender, sharply defined area of hyperkeratosis found usually on the foot (1).
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A corn has a central core that penetrates into the dermis.
Epidemiology
Calluses and corns are common skin conditions.
Risk Factors
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Activity: Occupational (eg, manual workers); musicians (eg, guitarists); athletic activities that apply increased stress to the skin (ie, racquet sports—hands, runners—feet, rowers—hands, sacrum) (2)
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Ill-fitting footwear: Tight, loose irregularities in shoe, or not wearing shoes (3)
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Bony prominences (4)
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Faulty foot mechanics or foot structure (3)
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Toe deformities
General Prevention
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Proper footwear (low-heeled, a soft upper portion, and wide toebox)
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Orthotics
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Toe separators
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Place felt pads over bony prominences or areas of increased friction to the skin.
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Wear gloves to protect the hands.
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Keep the hands and feet skin soft by applying a moisturizer (5).
Etiology
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Calluses and corns develop as a result of hyperkeratosis, a normal physiologic response of the skin to chronic friction, pressure, or trauma and commonly occur over bony prominences (1).
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Calluses commonly develop overlying bony prominences as a normal adaptation of the body to protect the skin when chronic pressure or friction is encountered (3,4).
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Abnormal stresses may be either extrinsic (eg, tight toebox) or intrinsic (eg, hammertoe) or a combination of both (3).
Diagnosis
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The diagnosis of calluses and corns is based upon their clinical appearance.
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Radiographs may be obtained if your physician suspects an underlying bony prominence is a contributing factor.
History
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Corns and calluses are typically located at sites of friction, pressure, repetitive trauma, or at bony prominences.
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Factors that typically provoke the formation of corns and calluses are:
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Sports that require cutting, turning, and sudden stops
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Occupations that are categorized as manual labor requiring the repetitive use of the hands or kneeling, such as a carpenter or landscaper
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Leisure activity that involves activities that cause repeated friction or pressure
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Poorly fitting footwear
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Coexisting illnesses (eg, diabetes)
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Inherited disposition (autosomal-dominant inheritance)
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Physical Exam
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The most common site for calluses is under the metatarsal heads and over bony prominences; may occur anywhere on the skin as a result of friction (4).
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A callus may be asymptomatic or painful, often appearing as a thick yellowish plaque that retains the natural skin lines (helps distinguish from warts) (2).
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A hard corn is a dry horny mass found commonly over the interphalangeal joints (dorsally) or the 5th toe (dorsolaterally).
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Soft corns are extremely painful; occur interdigitally; skin appears white and macerated; commonly located between the 4th interdigital space (often mistaken for tinea).
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Observe gait and the alignment of the feet for any faulty mechanics.
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Note the location and appearance of the hyperkeratotic lesions:
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Common sites for corns and calluses: Plantar surface (over the metatarsal heads, sides of the arch, and the heel) and dorsum of the foot (over the interphalangeal joints)
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Common sites for calluses on hands: Palmar surface and over metacarpophalangeal joints
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Palpate for any abnormal bony prominences.
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Assess for pain or tenderness.
P.61
Diagnostic Tests & Interpretation
Physical examination of the area is typically all that is necessary to make the diagnosis.
Imaging
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Usually not necessary
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Radiographs: Hands and weight-bearing views of the feet used to identify bony prominences or abnormalities (3)
Differential Diagnosis
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Verruca vulgaris or plantaris (differentiated by paring the skin: The corn becomes more normal in appearance and the wart displays the characteristic tiny red dots when pared)
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Tinea pedis (interdigital)
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Psoriatic plaque: Hyperkeratosis with red base
Treatment
Treatment is aimed at providing symptomatic relief and avoiding the underlying mechanical forces that caused the development of the callus or corn (1,2,3,5)[C]:
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Careful and regular paring
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Use an emery board or a pumice stone daily, if necessary, to remove excess thickened skin.
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The pumice stone works best after bathing when the thickened skin has softened.
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Soft corn: Toe separator or lamb's wool
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Doughnut-shaped corn pads
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Proper footwear with soft upper and a roomy toebox
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Orthotics can reduce pressure by redistributing forces.
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Use a skin-softening cream to prevent cracking of the callus or corn.
Medication
Antibiotics are only indicated when there is evidence of an infected corn or callus.
First Line
Salicylic acid (40%): Careful application or pads containing keratolytic agents (2)
Surgery/Other Procedures
Surgery may be required to correct the bony abnormalities or deformities, and is indicated only if all conservative measures have failed (3).
Ongoing Care
Follow-Up Recommendations
Follow-up is needed for ongoing corns and calluses despite conservative management, signs of infection, or severe pain.
Patient Monitoring
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Diabetics, the elderly, and individuals with peripheral arterial disease or peripheral neuropathy should consult with their healthcare providers before initiating treatment for calluses or corns.
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These individuals should be monitored closely for signs of nonhealing or infection.
References
1. Freeman DB. Corns and calluses resulting from mechanical hyperkeratosis. Am Fam Physician. 2002;65:2277–2280.
2. Cordoro KM, Ganz JE. Training room management of medical conditions: sports dermatology. Clin Sports Med. 2005;24:565–598, viii–ix.
3. Singh D, Bentley G, Trevino SG. Callosities, corns, and calluses. BMJ. 1996;312:1403–1406.
4. Spink MJ, Menz HB, Lord SR. Distribution and correlates of plantar hyperkeratotic lesions in older people. J Foot Ankle Res. 2009;2:8.
5. Robbins JM. Recognizing, treating, and preventing common foot problems. Cleve Clin J Med. 2000;67:45–47, 51–52, 55–56.
Codes
ICD9
700 Corns and callosities