Callus - Wikipedia Callus This article is about calluses and corns of human skin. For other uses, see Callus ( disambiguation ). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( January 2010 ) This page 's infobox may require expansion, verification, or otherwise need cleanup. Please make sure that the infobox meets Wikipedia 's guidelines for infoboxes. There might be relevant comments on the talk page. You may also want to view the infobox template page to view the full parameter list and read guidance on usage of that infobox. Callus Examples of callus found on the toe Specialty Dermatology A callus is an area of thickened skin 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 and incorrectly fitting footwear. Calluses are generally not harmful, but may sometimes lead to other problems, such as an skin ulceration or infection or cause the sufferer to try and offload the effected painful area, which can place excessive stress on the asymptomatic side. Contents 1 Cause 1.1 Corns 2 Prevention 3 Treatment 3.1 Diabetes 4 Other meanings 5 See also 6 Notes 7 References 8 External links Cause Normally, a callus will form on any part of the skin exposed to friction over a long period of time. For example, people often develop calluses on the middle finger of their dominant hand due to writing with a pen or pencil. Another cause is from playing string instruments like the guitar or the violin ; calluses will develop on the four fingers of the hand used in holding the strings down to the fingerboard, and sometimes on the fingers of the hand used for pizzicato or strumming. Weightlifters commonly experience callus on the upper - palm area due to repeated friction. Calluses are also very common on the fingers of rock climbers on almost all of their fingers. There are many activities that can result in the formation of a callus, which may even be viewed as a badge of experience and commitment to the activity. On the feet, calluses commonly form on the metatarsal - phalangeal joint area ( `` balls of the foot ), heels and small toes due to the compression applied by tightly fitting shoes. Activities that are notorious for causing calluses include ( but are not limited to ) construction work, many sports, wood carving, playing musical instruments, use of a chef 's knife, rock climbing, hiking, martial arts, weight training, rowing, BMXing, dancing ( especially ballet ), chopping wood, monkey bars and wearing high heels. Tenpin bowlers will often develop calluses on their thumbs and occasionally their middle fingers from frequent bowling. Although often found on the foot ( where the most pressure and friction are applied ), calluses 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 a blister or abrasion instead. Biologically, calluses are formed by the accumulation of terminally undifferentiated keratinocytes in the outermost layer of skin. Though the cells of calluses are dead, they are quite resistant to mechanical and chemical insults due to extensive networks of cross-linked proteins and hydrophobic keratin intermediate filaments containing many disulfide bonds. Sometimes a callus occurs where there is no rubbing or pressure. These hyperkeratoses can have a variety of causes. Some toxic materials, 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. Corns Main article : Corn ( medicine ) Painful corns 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. The hard part at the center of the corn resembles 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. 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 the 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. The specific diagnostic workup and treatments for corns may differ substantially from other forms of calluses. Prevention Corns and calluses are easier to prevent than to treat. When it is usually not desirable to form a callus, minimizing rubbing and pressure will prevent callus formation. Footwear should be properly fitted, 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 A person with callus at the barber surgeon 's, 17th century 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 silicon carbide sandpaper or filed down with a callus shaver, or pared down by a professional such as a podiatrist. 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. Callus formation is seen in high numbers of patients with diabetes, and together with absent foot pulses and formation of hammer toe, this may be an early sign of individuals at an increased risk for foot ulcers. 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. Fortunately, this process can be prevented at several places. Diabetic foot infections are the leading cause of diabetic limb amputation. Other meanings 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. This is a type of tissue culture, and can be started from almost any part of the plant, although tissues taken from the vicinity of meristems usually produce the best results. The term has also been used in orthopedic medicine to describe heterogeneous tissue involved in the intermediate stages of bone healing. In English, the adjective `` callous '' means insensitive or unfeeling, similarly to how calluses can cause a loss of pain sensitivity in the affected area. See also Hyperkeratosis Callosity Catagmatic Notes Jump up ^ Tantisiriwat N, Janchai S ( Dec 1991 ). `` Transglutaminases : multifunctional cross-linking enzymes that stabilize tissues ''. The FASEB Journal. 5 ( 15 ) : 3071 -- 7. PMID 1683845. Jump up ^ eMedicine > Clavus By Nanette Silverberg. Updated : Apr 9, 2010 Jump up ^ Erstad, Shannon ( 6 March 2008 ). `` Foot problems : Finding the right shoes ''. WebMD Medical Reference from Healthwise. Healthwise. `` How do I find the right shoes ? ''. Retrieved 2010 - 06 - 10. You should not have to `` break in '' shoes if they fit properly. Jump up ^ Corns and calluses : Treatments and drugs. Mayo Clinic. Retrieved July 23, 2009. ^ Jump up to : Alavi A, Sanjari M, Haghdoost A, Sibbald RG ( April 2009 ). `` Common foot examination features of 247 Iranian patients with diabetes ''. Int Wound J. 6 ( 2 ) : 117 -- 22. doi : 10.1111 / j. 1742 - 481X. 2009.00583. x. PMID 19432661. - 12 % having callus formation Jump up ^ Tantisiriwat N, Janchai S ( July 2008 ). `` Common foot problems in diabetic foot clinic ''. J Med Assoc Thai. 91 ( 7 ) : 1097 -- 101. PMID 18839852. - 56 % having callus present Jump up ^ Stern, Kingsley ( 1997 ). Introductory Plant Biology ( seven ed. ). Wm. C. Brown Publishers. References Taber 's Cyclopedic Medical Dictionary, 15th Edition, CL Thomas, M.D., M.P.H., editor, F.A. Davis Company, Philadelphia, PA, 1985. The Merck Manual of Medical Information, Home Edition, R Berkow, M.D., et al., editors, Merck Research Laboratories, Whitehouse Station, NJ, 1997. External links Classification V T D ICD - 10 : L84 ICD - 9 - CM : 700 MeSH : D002145 This article is about callous. For a definition of the word `` callus '', see the Wiktionary entry callus. 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 ( benign fibrous histiocytoma ) 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 syphilis 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 / solar 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 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 Cutaneous keratosis, ulcer, atrophy, and necrobiosis ( L82 -- L94, 700 -- 701.5 ) Epidermal thickening keratoderma : Keratoderma climactericum Paraneoplastic keratoderma Acrokeratosis paraneoplastica of Bazex Aquagenic keratoderma Drug - induced keratoderma psoriasis Keratoderma blennorrhagicum keratosis : Seborrheic keratosis Clonal seborrheic keratosis Common seborrheic keratosis Irritated seborrheic keratosis Seborrheic keratosis with squamous atypia Reticulated seborrheic keratosis Dermatosis papulosa nigra Keratosis punctata of the palmar creases other hyperkeratosis : Acanthosis nigricans Confluent and reticulated papillomatosis Callus Ichthyosis acquisita Arsenical keratosis Chronic scar keratosis Hyperkeratosis lenticularis perstans Hydrocarbon keratosis Hyperkeratosis of the nipple and areola Inverted follicular keratosis Lichenoid keratosis Multiple minute digitate hyperkeratosis PUVA keratosis Reactional keratosis Stucco keratosis Thermal keratosis Viral keratosis Warty dyskeratoma Waxy keratosis of childhood other hypertrophy : Keloid Hypertrophic scar Cutis verticis gyrata Necrobiosis / granuloma Necrobiotic / palisading Granuloma annulare Perforating Generalized Subcutaneous Granuloma annulare in HIV disease Localized granuloma annulare Patch - type granuloma annulare Necrobiosis lipoidica Annular elastolytic giant cell granuloma Granuloma multiforme Necrobiotic xanthogranuloma Palisaded neutrophilic and granulomatous dermatitis Rheumatoid nodulosis Interstitial granulomatous dermatitis / Interstitial granulomatous drug reaction Foreign body granuloma Beryllium granuloma Mercury granuloma Silica granuloma Silicone granuloma Zirconium granuloma Soot tattoo Tattoo Carbon stain Other / ungrouped eosinophilic dermatosis Granuloma faciale Dermis / localized CTD Cutaneous lupus erythematosus chronic : Discoid Panniculitis subacute : Neonatal ungrouped : Chilblain Lupus erythematosus -- lichen planus overlap syndrome Tumid Verrucous Rowell 's syndrome Scleroderma / Morphea Localized scleroderma Localized morphea Morphea -- lichen sclerosus et atrophicus overlap Generalized morphea Atrophoderma of Pasini and Pierini Pansclerotic morphea Morphea profunda Linear scleroderma Atrophic / atrophoderma Lichen sclerosus Anetoderma Schweninger -- Buzzi anetoderma Jadassohn -- Pellizzari anetoderma Atrophoderma of Pasini and Pierini Acrodermatitis chronica atrophicans Semicircular lipoatrophy Follicular atrophoderma Linear atrophoderma of Moulin Perforating Kyrle disease Reactive perforating collagenosis Elastosis perforans serpiginosa Perforating folliculitis Acquired perforating dermatosis Skin ulcer Pyoderma gangrenosum Other Calcinosis cutis Sclerodactyly Poikiloderma vasculare atrophicans Ainhum / Pseudo-ainhum Retrieved from `` https://en.wikipedia.org/w/index.php?title=Callus&oldid=837247696 '' Categories : Foot diseases Skin conditions resulting from physical factors Hidden categories : Articles needing additional references from January 2010 All articles needing additional references Wikipedia infobox cleanup Infobox medical condition ( new ) All articles with unsourced statements Articles with unsourced statements from November 2008 Articles with unsourced statements from June 2010 Talk Contents About Wikipedia Bân - 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Question: where do calluses on your feet come from
Answer: repeated friction