callus

Definition

A corn is a small, painful, raised bump on the outer skin layer. A callus is a rough, thickened patch of skin.

Description

Corns and calluses are one of the three major foot problems in the United States. The other two are foot infections and toenail problems. Corns and calluses affect about 5% of the population.

Corns usually appear on non-weight-bearing areas like the outside of the little toe or the tops of other toes. Women have corns more often than men, probably because women wear high-heeled shoes and other shoes that do not fit properly. Corns have hard cores shaped like inverted pyramids. Sharp pain occurs whenever downward pressure is applied, and a dull ache may be felt at other times.

Calluses occur most often on the heels and balls of the feet, the knees, and the palms of the hands. However, they can develop on any part of the body that is subject to repeated pressure or irritation. Calluses are usually more than an inch wide—larger than corns. They generally don't hurt unless pressure is applied.

A hard corn is a compact lump with a thick core. Hard corns usually form on the tops of the toes, on the outside of the little toe, or on the sole of the foot.

A soft corn is a small, inflamed patch of skin with a smooth center. Soft corns usually appear between the toes.

A seed corn is the least common type of corn. Occurring only on the heel or ball of the foot, a seed corn consists of a circle of stiff skin surrounding a plug of cholesterol.

A plantar callus, a callus that occurs on the sole of the foot, has a white center. Hereditary calluses develop where there is no apparent friction, run in families, and occur most often in children.

— Maureen Haggerty

1. 1. A localized thickening and enlargement of the horny layer of the skin. Also called callosity.
   2. The hard bony tissue that develops around the ends of a fractured bone during healing.
2. Botany.
   1. Undifferentiated tissue that develops on or around an injured or cut plant surface or in tissue culture.
   2. The hardened, sometimes sharp base of the floret of certain grasses.

[Latin, masculine of callum.]

For more information on callus, visit Britannica.com.

The tissue near and about the broken fragments of a bone that becomes involved in the repair of the fracture through various stages of exudate, fibrosis, and new bone formation.

Definition

A corn is an overgrowth of skin on a bony prominence, usually occurring on the feet and toes. It manifests as a rough and painful bump. A callus is a rough, thickened lump of dead skin that is usually painless. It may be found on the feet, the hands, or anywhere else there is repeated friction and pressure.

Description

Corns and calluses affect about 5% of the population of the United States. Women have corns more often than men, probably due to wearing ill-fitted shoes more often. Although calluses may form anywhere on the body, they are generally found on the heels and balls of the feet, the knees, and the palms of the hands. Calluses are usually larger than corns—they may measure more than an inch (2.5 cm) wide. Calluses usually only hurt if pressure is applied to them.

Causes & Symptoms

Corns and calluses form to prevent injury to skin that is repeatedly pinched, rubbed, or irritated. Hereditary calluses may develop where there is no apparent friction. This condition runs in families and occurs most often in children.

The most common causes of the formation of corns and calluses are:

• shoes that have very high heels and shoes that do not fit properly
• tight socks or stockings
• deformities of the toes
• walking or standing on a hard surface for an extended time
• jobs or hobbies that cause steady or recurring pressure on the same spot

Corns may be extremely sore and surrounded by inflamed, swollen skin. A sharp pain will probably occur whenever downward pressure is applied, and a dull ache may be felt at other times.

Diagnosis

Corns can be recognized on sight. They are sometimes mistaken for warts. However, if the lesion is a wart, it will bleed when scraped with a sharp implement. A callus will not bleed, but will shed a layer of dead skin. This can provide the basis of a general diagnosis.

Treatment

Standing and walking correctly can sometimes eliminate excess foot pressure and minimize the development and recurrence of corns and calluses. Bodywork systems such as Aston-Patterning, the Feldenkrais method, and rolfing, may help to correct body imbalances that lead to corns and calluses.

Two or three daily applications of calendula (Calendula officinalis) salve can soften skin and prevent inflammation. A mixture of one teaspoon of lemon juice, one teaspoon of dried chamomile (Martricaria recutita), and one crushed garlic clove (Allium sativa) can be applied directly to dissolve thickened skin.

A recommended Ayurvedic remedy is the nightly application of a paste made by combining one teaspoon of aloe vera gel with one half teaspoon of turmeric (Curcuma longa). The corn or callus should be covered with the paste and bandaged overnight. It should be soaked in warm water for 10 minutes every morning, and given a daily massage with mustard oil (Brassica cruciferae).

Allopathic Treatment

The attention of a physician may be required if there is numbness, reduced feeling, or severe pain. Occasionally, an orthopedist may have to perform surgery to correct toe deformities or remove bits of bone that may be causing corns or calluses to develop. Medical attention is not usually required unless diabetes mellitus, poor circulation, or other problems make self-care difficult. The first step in home care of corns and calluses is to identify and eliminate sources of pressure and friction. Doughnut-shaped pads, wads of cotton, lamb's wool, or other kinds of inserts can be used to cushion affected areas. Soaking the feet in a solution of Epsom salts, or using hydrocortisone creams, petroleum jelly, or lanolin lotions can soften calluses. After which, they can be reduced or removed by rubbing the area with a pumice stone. This is not recommended for corns, however, as rubbing just makes them more painful.

It is important to consult with a healthcare provider if there is broken skin because it may become infected. In the case of an infection, affected layers of skin need to be removed, and pus may need to be drained. Oral antibiotics may be given to eliminate the infection. Cortisone may be injected into the affected area to decrease pain or inflammation.

Expected Results

Most corns and calluses disappear within three weeks after the pressure that caused them is eliminated. However, if the causes of the condition are not remedied completely, or are allowed to recur, the corns and calluses may return. If there is continual pain associated with corns, it can change the way a person stands or walks. Such changes may eventually cause pain and dysfunction in the ankles, back, hips, or knees.

If a corn develops near a toe joint, bursitis may result, causing severe pain and inflammation. If cracks or other breaks in the skin develop, a staph infection may result. This is especially serious for people who have diabetes or poor circulation, as gangrene may develop from a resistant infection.

Prevention

Corns and calluses can usually be prevented by wearing shoes that fit properly. Feet should be measured, while standing, whenever buying new shoes. It is best to shop for shoes late in the day, when feet are likely to be swollen. It is also important to buy shoes with toe-wiggling room and to try new shoes on both feet. Pointytoed shoes and high heels should be avoided. Worn down or uneven shoe soles and heels should be replaced or repaired. Corrective footwear or special insoles may be necessary. Socks and stockings should also be fitted appropriately at the feet. Gloves, kneepads, and other protective gear should be worn as needed to prevent rubbing and friction, especially when engaging in heavy work or sports activities. Cutting or paring dead skin should be avoided, as it may lead to further injury or infection.

Resources

Books

Editors of Time-Life Books. The Medical Advisor: The Complete Guide to Alternative and Conventional Treatments. Alexandria, VA: Time-Life, 1996.

Gottlieb, Bill, ed. New Choices in Natural Healing. Emmaus, PA: Rodale Press, 1995.

Organizations

American Podiatric Medical Association. 9312 Old Georgetown Road, Bethesda, MD 20814-1698. http://www.apma.org.

[Article by: Patience Paradox]

1. Tissue containing blood and bone cells that form around bone following a fracture. Callus formation is an essential part of healthy bone repair.

2. See callosity.

1. localized hyperplasia of the horny layer of the epidermis due to pressure or friction. In dogs, these often form over pressure points such as the elbow, hock and (in some breeds) sternum, particularly if the animal is sleeping on a hard surface.
2. an unorganized network of woven bone formed about the ends of a broken bone; it is absorbed as repair is completed (provisional callus), and ultimately replaced by true bone (definitive callus).

• bridging c. — bridging the callus gap.
• external c. — around the outside of a fracture.
• hard c. — fully mineralized.
• hypertrophic c. — a form of delayed healing in which fibrocartilage forms between fracture fragments, resulting in a false callus. Called also elephant's foot callus.
• internal c. — between the ends of fractured bones.
• periosteal c. — new bone formed by the proliferation of periosteal osteogenic cells.
• provisional c. — a subsequently remodeled callus.
• c. pyoderma — secondary bacterial infection, particularly of pressure point calluses in dogs; can be extensive with deep pyogenic inflammation.
• soft c. — the originating fibobrocellular tissue before calcification.
• sternal c. — may develop over a prominent sternum in some breeds of dogs, particularly Dachshunds, in response to pressure.
• temporary c. — see provisional callus (above).

1. The corklike tissue that is developed to cover wounds in the bark of a tree or shrub.
2. A zone of rapidly dividing cells at the base of a cutting that precedes root formation.

Tutor's tip: The doctor was "callous" (insensitive, cold in manner) when I showed her the painful "callus" (thick hard skin layer) on my finger.

This article is about calluses and corns of human skin. For other uses, see Callus (disambiguation).

For a definition of the word callous, see the Wiktionary entry callous.

Callus
Classification and external resources
ICD-10	L84.
ICD-9	700
MeSH	D002145

A callus (or callosity) is an especially toughened area of skin which has become relatively thick and hard in response to repeated friction, pressure, or other irritation. Rubbing that is too frequent or forceful will cause blisters rather than allow calluses to form. Since repeated contact is required, calluses are most often found on feet because of frequent walking. Guitarists often also develop calluses on their fingertips due to the frequent friction on the strings. Bowlers will often develop calluses on the thumb as well as their middle and ring fingers due to the friction caused in releasing the ball. Bicycle riders can also get calluses especially if they are not wearing gloves. While swinging on the monkey bars in a play ground, little children often develop calluses just above the palm of their hands. Calluses are generally not harmful, but may sometimes lead to other problems, such as skin ulceration or infection.

In botany, the term is also used to describe a condition of thickened surfaces of leaves or other plant parts. A callus also can refer to an undifferentiated plant cell mass grown on a culture medium, which can be put into a bioreactor to produce genetically identical cells.

Contents 1 Development 2 Prevention 3 Treatment 4 Corns 5 Diabetes 6 See also 7 References 8 External links

Development

Although usually found on the foot (where the most pressure and friction are applied), callouses can occur anywhere on the body as a reaction to moderate, constant "grinding" pressure. It is the natural reaction of the palmar or plantar skin. Too much friction occurring too fast for the skin to develop a protective callus will cause blisters instead.

Players of string instruments will develop calluses on their fingers purposefully with frequent play. The callouses actually help the player as the thicker skin protects the fingertips and increases the fingers' ease of sliding on the strings-- extended play is often painful before the callouses develop. Drummers can also develop callouses on their feet or hands, generally viewing these as boons. Callouses on the feet are more common in metal drummers, where double bass drumming is used more often. Use of older sticks will also cause callus on the palms and fingers of a drummer. Percussionists beginning to develop 4-mallet technique often develop blisters in the palms of their hands or in between the index and middle fingers if the aggressiveness of their play is too much for the yet-to-callus skin to handle. Frequent pen use can also develop a light callus on the middle finger, where the pen is in constant contact and friction with the skin.

Rowers generally develop calluses at the base of the fingers on the palm, or on the fingers themselves. Duct tape or gloves are sometimes employed to alleviate the friction of turning oar handles.

Sailors will also develop callouses on their hands, due to the regularity of hauling on lines.

People with bunions may find painful calluses behind the second or third toe. These are caused by unequal pressure and rubbing on the smaller toes. Such callouses can be very painful and often do not respond to trimming of the callus, soft materials, or orthotic devices. It is not the callous that causes pain, but rather the severe imbalance in the function of the foot that is taking its toll.

Shoes can produce corns by rubbing against the top of the toes or foot. Continued irritation may cause pain. Stretching out the shoe to reduce rubbing may reduce the contact and alleviate the pain, but the corn may remain. If a toenail or a fingernail rubs against the skin, pinching it between surfaces for a period of time, a corn can form at the edge of the nail. These corns are difficult to treat because the nail is frequently the primary cause.

Sometimes a callous occurs where there is no rubbing or pressure. These hyperkeratoses can have a variety of causes. Some toxins, such as arsenic, can cause thick palms and soles. Some diseases, such as syphilis, can cause thickening of the palms and soles as well as pinpoint hyperkeratoses. There is a benign condition called keratosis palmaris et plantaris, which produces corns in the creases of the fingers and non-weight bearing spaces of the feet. Some of this may be caused by actinic keratosis, which occurs due to overexposure to sun or with age and hormonal shifts.

Prevention

Corns and calluses are easier to prevent than to treat. When it is not desirable to form a callus, minimizing rubbing and pressure will prevent callus formation. Footwear should be properly fitted and broken in, gloves may be worn, and protective pads, rings or skin dressings may be used. People with poor circulation or sensation should check their skin often for signs of rubbing and irritation so they can minimize any damage.

Treatment

Calluses and corns may go away by themselves eventually, once the irritation is consistently avoided. They may also be dissolved with keratolytic agents containing salicylic acid, sanded down with a pumice stone, or pared down by a medical professional such as a podiatrist.^[1]

Corns

Examples of clavi found on the toe

A corn (or clavus, plural clavi) is a specially-shaped callus of dead skin that usually occurs on thin or glabrous (hairless and smooth) skin surfaces, especially on the dorsal surface of toes or fingers. They can sometimes occur on the thicker palmar or plantar skin surfaces. Corns form when the pressure point against the skin traces an elliptical or semi-elliptical path during the rubbing motion, the center of which is at the point of pressure, gradually widening. If there is constant stimulation of the tissue producing the corns, even after the corn is surgically removed, the skin may continue to grow as a corn.^{[citation needed]}

The hard part at the center of the corn resembles a barley hare, that is, a funnel with a broad raised top and a pointed bottom. Because of their shape, corns intensify the pressure at the tip and can cause deep tissue damage and ulceration. Hard corns are especially problematic for people with insensitive skin due to diabetes, etc. The scientific name for a corn is heloma (plural helomata). A hard corn is called a heloma durum, while a soft corn is called a heloma molle.

The location of soft corns tends to differ from that of hard corns. Hard corns occur on dry, flat surfaces of skin. Soft corns (frequently found between adjacent toes) stay moist, keeping the surrounding skin soft. The corn's center is not soft, however, but indurated.

Diabetes

People with diabetes face special skin challenges. Because diabetes affects the capillaries, the small blood vessels which feed the skin, thickening of the skin with callus increases the difficulty of supplying nutrients to the skin. The stiffness of a callus or corn, coupled with the shear and pressure that caused it, may tear the capillaries or adjoining tissue, causing bleeding within the callus or corn.

Often, bleeding within a callus is an early sign of diabetes, even before elevated blood sugars may be noticed. Although the bleeding can be small, sometimes small pools of blood or hematoma are formed. The blood itself is an irritant, a foreign body within the callus that makes the area burn or itch. If the pool of blood is exposed to the outside, infection may follow. Infection may also lead to ulceration. Luckily, this process can be prevented at several places, but such infections can become life-threatening. Diabetic foot infections are the leading cause of diabetic limb amputation.

See also

• Hyperkeratosis
• Catagmatic
• Zebibah

References

This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations where appropriate. (April 2009)

1. ^ Corns and calluses: Treatments and drugs. Mayo Clinic. Retrieved July 23, 2009.

1. Taber's Cyclopedic Medical Dictionary, 15th Edition, CL Thomas, M.D., M.P.H., editor, F.A. Davis Company, Philadelphia, PA, 1985.

2. The Merck Manual of Medical Information, Home Edition, R Berkow, M.D., et al., editors, Merck Research Laboratories, Whitehouse Station, NJ, 1997.

External links

• MayoClinic.com - Corns and calluses

v • d • e Diseases of the skin and appendages by morphology Growths Epidermal wart · callus · seborrheic keratosis · acrochordon · molluscum contagiosum · actinic keratosis · squamous cell carcinoma · basal cell carcinoma · merkel cell carcinoma · nevus sebaceous · trichoepithelioma Pigmented Freckles · lentigo · melasma · nevus · melanoma Dermal and subcutaneous epidermal inclusion cyst · hemangioma · dermatofibroma · keloid · lipoma · neurofibroma · xanthoma · Kaposi's sarcoma · infantile digital fibromatosis · granular cell tumor · leiomyoma · lymphangioma circumscriptum · myxoid cyst Rashes With epidermal involvement Eczematous contact dermatitis · atopic dermatitis · seborrheic dermatitis · stasis dermatitis · lichen simplex chronicus · Darier's disease · glucagonoma syndrome · langerhans cell histiocytosis · lichen sclerosus · pemphigus foliaceus · Wiskott-Aldrich syndrome · Zinc deficiency Scaling psoriasis · tinea (corporis · cruris · pedis · manuum · faciei) · pityriasis rosea · secondary syphillis · mycosis fungoides · systemic lupus erythematosus · pityriasis rubra pilaris · parapsoriasis · ichthyosis Blistering herpes simplex · herpes zoster · varicella · bullous impetigo · acute contact dermatitis · pemphigus vulgaris · bullous pemphigoid · dermatitis herpetiformis · porphyria cutanea tarda · epidermolysis bullosa simplex Papular scabies · insect bite reactions · lichen planus · miliaria · keratosis pilaris · lichen spinulosus · transient acantholytic dermatosis · lichen nitidus · pityriasis lichenoides et varioliformis acuta Pustular acne vulgaris · acne rosacea · folliculitis · impetigo · candidiasis · gonococcemia · dermatophyte · coccidioidomycosis · subcorneal pustular dermatosis Hypopigmented tinea versicolor · vitiligo · pityriasis alba · postinflammatory hyperpigmentation · tuberous sclerosis · idiopathic guttate hypomelanosis · leprosy · hypopigmented mycosis fungoides Without epidermal involvement Red Blanchable Erythema Generalized drug eruptions · viral exanthems · toxic erythema · systemic lupus erythematosus Localized cellulitis · abscess · boil · erythema nodosum · carcinoid syndrome · fixed drug eruption Specialized urticaria · erythema (multiforme · migrans · gyratum repens · annulare centrifugum · ab igne) Nonblanchable Purpura Macular thrombocytopenic purpura · actinic purpura Papular disseminated intravascular coagulation · vasculitis Indurated scleroderma/morphea · granuloma annulare · lichen sclerosis et atrophicus · necrobiosis lipoidica Miscellaneous disorders Ulcers Hair telogen effluvium · androgenic alopecia · trichotillomania · alopecia areata · systemic lupus erythematosus · tinea capitis · loose anagen syndrome · lichen planopilaris · folliculitis decalvans · acne keloidalis nuchae Nail onychomycosis · psoriasis · paronychia · ingrown nail Mucous membrane aphthous stomatitis · oral candidiasis · lichen planus · leukoplakia · pemphigus vulgaris · mucous membrane pemphigoid · cicatricial pemphigoid · herpesvirus · coxsackievirus · syphilis · systemic histoplasmosis · squamous cell carcinoma

v • d • e Diseases of the skin and subcutaneous tissue (integumentary system) (L, 680-709) Infections Bacterial skin disease Staphylococcus (Staphylococcal scalded skin syndrome, Impetigo, Boil, Carbuncle) · Strep (Impetigo) · Corynebacterium (Erythrasma) Viral skin disease Wart · Molluscum contagiosum · Erythema infectiosum · Exanthema subitum · Herpes simplex (Herpetic whitlow, Eczema herpeticum) General Cellulitis (Paronychia) · Acute lymphadenitis · Pilonidal cyst · Pimple (Pustule) Bullous disorders acantholysis (Pemphigus, Transient acantholytic dermatosis) · Pemphigoid (Bullous, Cicatricial, Gestational) · Dermatitis herpetiformis Inflammatory Dermatitis and eczema Atopic dermatitis · Seborrhoeic dermatitis (Dandruff, Cradle cap) · Contact dermatitis (Diaper rash, Urushiol-induced contact dermatitis) · Erythroderma · Lichen simplex chronicus/Prurigo nodularis · Itch (Pruritus ani, Pruritus scroti, Pruritus vulvae) · Nummular dermatitis · Dyshidrosis · Pityriasis alba Papulosquamous disorders Psoriasis (Psoriatic arthritis) · Parapsoriasis (Pityriasis lichenoides et varioliformis acuta, Pityriasis lichenoides chronica, Lymphomatoid papulosis) · other pityriasis (Pityriasis rosea, Pityriasis rubra pilaris) · other lichenoid (Lichen planus, Lichen nitidus) Urticaria Dermatographic urticaria · Cold urticaria · Cholinergic urticaria · Solar urticaria Erythema Erythema multiforme/ drug eruption Stevens-Johnson syndrome · Toxic epidermal necrolysis · Erythema nodosum  · Acute generalized exanthematous pustulosis Other erythema Erythema annulare centrifugum · Erythema marginatum · Keratolytic winter erythema · Necrolytic migratory erythema · Erythema toxicum Radiation-related disorders Sunburn · actinic rays (Actinic keratosis, Actinic cheilitis) · Polymorphous light eruption (Acne aestivalis) · Radiodermatitis · Erythema ab igne Pigmentation/ Dyschromia hypopigmentation (Albinism, Vitiligo) · hyperpigmentation (Melasma, Freckle, Café au lait spot, Lentigo/Liver spot, Acanthosis nigricans, Acral acanthotic anomaly) Other skin keratosis/hyperkeratosis (Seborrheic keratosis, Callus) · other epidermal thickening (Ichthyosis acquisita, Palmoplantar keratoderma) skin ulcer (Pyoderma gangrenosum, Bedsore) Cutaneous Markers of Internal Malignancy (Florid cutaneous papillomatosis, acanthosis nigricans, sign of Leser-Trelat) atrophic (Lichen sclerosus, Acrodermatitis chronica atrophicans) necrobiosis (Granuloma annulare, Necrobiosis lipoidica) · other granuloma (Granuloma faciale, Pyogenic granuloma) cutaneous vasculitis (Livedoid vasculitis, Erythema elevatum diutinum) Connective tissues collagen disease: Keloid localized connective tissue disorders: Lupus erythematosus (Discoid lupus erythematosus, Subacute cutaneous lupus erythematosus) · Scleroderma/Morphea · Linear scleroderma · Calcinosis cutis · Sclerodactyly · Ainhum integument, SF, LCT navs: anat/physio, noncongen/congen/neoplasia, symptoms+signs/eponymous, proc

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Dansk (Danish)
n. - callus, bruskagtigt bindevæv dannet efter knoglebrud
v. intr. - danne hård hud, danne bruskagtigt bindevæv

Nederlands (Dutch)
eelt, litteken(weefsel), callus

Français (French)
n. - cal, cals, durillon
v. intr. - former des durillons

Deutsch (German)
n. - (Physiol.) Schwiele, Kallus, (Med.) Knochennarbe, (Bot.) Wundgewebe
v. - einen Kallus bilden

Ελληνική (Greek)
n. - (φυσιολ.) τύλος, κάλος

Italiano (Italian)
callosità, callo, durone, tiloma

Português (Portuguese)
adj. - calosidade
n. - calo (m), calo (m) ósseo (Med.)

Русский (Russian)
костная мозоль

Español (Spanish)
n. - callo
v. intr. - hacerse un callo

Svenska (Swedish)
n. - kallus, sårvävnad
v. - göra valkig

中文（简体）(Chinese (Simplified))
皮肤的硬结, 愈合组织, 胼胝, 结硬皮, 生老茧, 结痂

中文（繁體）(Chinese (Traditional))
n. - 皮膚的硬結, 癒合組織, 胼胝
v. intr. - 結硬皮, 生老繭, 結痂

한국어 (Korean)
n. - 굳은 살, 유합 조직
v. intr. - ~를 형성하다

日本語 (Japanese)
n. - 胼胝, たこ, 癒傷組織, カルス, 皮膚硬結

العربيه (Arabic)
‏(الاسم) جز متصلب من الجلد (فعل) يسبب أو يتسبب في تصلب الجلد‏

עברית (Hebrew)
n. - ‮יבלת (בעור), צלקת‬
v. intr. - ‮נוצרה (יבלת)‬

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