Corns Clinical Presentation

  • Author: Daniel J Hogan, MD; Chief Editor: Dirk M Elston, MD   more...
 
Updated: Jul 13, 2010
 

History

Commonly, a patient reports the development of a localized growth on their foot or toes that causes pain with ambulation or when wearing shoes.[4]

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Physical

Corns are typically located between toe clefts, on the plantar aspect beneath prominent metatarsals, or on the dorsal aspect of toe joints.[5] The patient’s gait should be observed to identify irregular mechanics.[3] Additionally, surrounding erythema and heat may be present if the corn is acutely irritated.[2] Multiple physical signs, as follows, can be evaluated in order to differentiate between a clavus, callus, and wart:

  • Both plantar warts and hard corns can be tender, and both occur on the pressure points of the sole.
  • Direct pressure generally causes tenderness in a callus and clavi. Warts are tender with pressure applied from side to side.[4, 6]
  • Calluses have a waxy appearance after being pared, whereas corns produce a central keratin plug.[4] Plantar warts do not have a central core.
  • The absence of capillary dotting after paring hard corns distinguishes them from plantar warts.[3, 12]
  • Skin markings can be seen crossing the surface of calluses, but not warts or corns.[12]

A hard corn is a firm, dry, and tender lesion with a shiny polished surface. If the upper layers are pared away, a small, 1- to 2-mm translucent central core may be seen within the base of the lesion. Hard corns usually occur on the dorsolateral aspect of the fifth toe.[2] A plantar corn is a type of hard corn most commonly associated with a central core. These corns are located beneath the metatarsal heads of the toes.[2] Plantar corns that do not respond to conservative medical treatment are referred to as intractable plantar keratosis.[13] Note the image below.

Hard corn on the lateral surface of fifth toe. CouHard corn on the lateral surface of fifth toe. Courtesy of James K. DeOrio, MD.

A soft corn is boggy and macerated so that it appears white. Soft corns usually occur in the fourth interdigital space.[2]

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Causes

Both hard and soft corns are caused by pressure from unyielding structures.[2] Abnormal mechanical stress may be intrinsic or extrinsic (list adapted from Singh et al, “Callosities, corns, and calluses”[3] ).

Intrinsic factors include foot deformities (hammer toe, bunion)[14] ; abnormal foot mechanics (acquired or hereditary); and peripheral neuropathy.

Extrinsic factors include poorly fitting footwear and heavy activity (athletics).

A 2005 study conducted by Menz et al reported that in older populations, plantar pressures are significantly higher under callused regions of the foot.[15] This data supports the idea that increased pressures are related to a hyperkeratotic response and that the target for treatment should be eliminating excess pressures on the foot.

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Contributor Information and Disclosures
Author

Daniel J Hogan, MD  Clinical Professor of Internal Medicine (Dermatology), Nova Southeastern University College of Osteopathic Medicine; Investigator, Hill Top Research, Florida Research Center

Daniel J Hogan, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Contact Dermatitis Society, and Canadian Dermatology Association

Disclosure: Nothing to disclose.

Coauthor(s)

Amy Lynn Basile, DO, MPH  Sun Coast Hospital/Largo Medical Center, Largo, Florida

Amy Lynn Basile, DO, MPH is a member of the following medical societies: American Medical Association, American Osteopathic Association, and American Osteopathic College of Dermatology

Disclosure: Nothing to disclose.

Specialty Editor Board

Richard K Scher, MD  Adjunct Professor of Dermatology, University of North Carolina; Professor Emeritus of Dermatology, Columbia University

Richard K Scher, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American College of Physicians, American Dermatological Association, American Medical Association, Association of Military Surgeons of the US, International Society for Dermatologic Surgery, Noah Worcester Dermatological Society, and Society for Investigative Dermatology

Disclosure: Nothing to disclose.

David F Butler, MD  Professor of Dermatology, Texas A&M University College of Medicine; Chair, Department of Dermatology, Director, Dermatology Residency Training Program, Scott and White Clinic, Northside Clinic

David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, American Society for Dermatologic Surgery, American Society for MOHS Surgery, Association of Military Dermatologists, and Phi Beta Kappa

Disclosure: Nothing to disclose.

Jeffrey Meffert, MD  Assistant Clinical Professor of Dermatology, University of Texas School of Medicine at San Antonio

Jeffrey Meffert, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association, Association of Military Dermatologists, and Texas Dermatological Society

Disclosure: Nothing to disclose.

Catherine M Quirk, MD  Clinical Assistant Professor, Department of Dermatology, University of Pennsylvania

Catherine M Quirk, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Dermatology

Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD  Director, Ackerman Academy of Dermatopathology, New York

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

The authors and editors of eMedicine gratefully acknowledge the contributions of previous authors, (1) Ali Hendi, MD, (2) Douglas W. Kress, MD, and (3) Roger Patrick, MD, to the development and writing of this article.

References

  1. Freeman DB. Corns and calluses resulting from mechanical hyperkeratosis. Am Fam Physician. Jun 1 2002;65(11):2277-80. [Medline].

  2. Murphy GA. Lesser Toe Abnormalities: Corns (Helomata and Clavi). In: Canale ST, ed. Canale: Campbell's Operative Orthopaedics. 10th. St. Louis, Mo: Mosby; 2003:4063-5.

  3. Singh D, Bentley G, Trevino SG. Callosities, corns, and calluses. BMJ. Jun 1 1996;312(7043):1403-6. [Medline].

  4. Snider RK. Corns and Calluses. In: Greene WB, ed. Essentials of Musculoskeletal Care. 2nd ed. Rosemont, Ill: American Academy of Orthopaedic Surgeons; 2001:437-41.

  5. DeLauro TM, DeLauro NM. Corns and Calluses. In: Wolff K, Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, eds. Fitzpatrick's Dermatology in General Medicine. 7th ed. New York, NY: McGraw-Hill; 2008:97.

  6. Kennedy CTC, Burd DAR. Mechanical and Thermal Injury. In: Burns T, Breathnach SM, Cox N, Griffiths CE, eds. Rook's Textbook of Dermatology. 7th ed. London, England: Blackwell Science; 2004:22.

  7. Williams ML, Elias PM. Enlightened therapy of the disorders of cornification. Clin Dermatol. Jul-Aug 2003;21(4):269-73. [Medline].

  8. Dunn JE, Link CL, Felson DT, Crincoli MG, Keysor JJ, McKinlay JB. Prevalence of foot and ankle conditions in a multiethnic community sample of older adults. Am J Epidemiol. Mar 1 2004;159(5):491-8. [Medline].

  9. Menz HB, Morris ME. Footwear characteristics and foot problems in older people. Gerontology. Sep-Oct 2005;51(5):346-51. [Medline].

  10. Black JR, Hale WE. Prevalence of foot complaints in the elderly. J Am Podiatr Med Assoc. Jun 1987;77(6):308-11. [Medline].

  11. Benvenuti F, Ferrucci L, Guralnik JM, Gangemi S, Baroni A. Foot pain and disability in older persons: an epidemiologic survey. J Am Geriatr Soc. May 1995;43(5):479-84. [Medline].

  12. Habif TP. Warts, Herpes Simplex and other Viral Infections. In: Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 4th ed. St. Louis, Mo: Mosby; 2004:374-5.

  13. Mann RA, DuVries HL. Intractable plantar keratosis. Orthop Clin North Am. Jan 1973;4(1):67-73. [Medline].

  14. Coughlin MJ, Kennedy MP. Operative repair of fourth and fifth toe corns. Foot Ankle Int. Feb 2003;24(2):147-57. [Medline].

  15. Menz HB, Zammit GV, Munteanu SE. Plantar pressures are higher under callused regions of the foot in older people. Clin Exp Dermatol. Jul 2007;32(4):375-80. [Medline].

  16. Coughlin MJ. Common causes of pain in the forefoot in adults. J Bone Joint Surg Br. Aug 2000;82(6):781-90. [Medline].

  17. Bae JM, Kang H, Kim HO, Park YM. Differential diagnosis of plantar wart from corn, callus and healed wart with the aid of dermoscopy. Br J Dermatol. Jan 2009;160(1):220-2. [Medline].

  18. Sage RA, Webster JK, Fisher SG. Outpatient care and morbidity reduction in diabetic foot ulcers associated with chronic pressure callus. J Am Podiatr Med Assoc. Jun 2001;91(6):275-9. [Medline].

  19. Cordoro KM, Ganz JE. Training room management of medical conditions: sports dermatology. Clin Sports Med. Jul 2005;24(3):565-98, viii-ix. [Medline].

  20. Foster A, Edmonds ME, Das AK, Watkins PJ. Corn cures can damage your feet: an important lesson for diabetic patients. Diabet Med. Dec 1989;6(9):818-9. [Medline].

  21. Balkin SW. Silicone injection for plantar keratoses. Preliminary report. J Am Podiatry Assoc. Jan 1966;56(1):1-11. [Medline].

  22. Balkin SW. Injectable silicone and the foot: a 41-year clinical and histologic history. Dermatol Surg. Nov 2005;31(11 Pt 2):1555-9; discussion 1560. [Medline].

  23. Field LM. Letter: injectable silicone for painful interdigital neurovascular clavi and verrucae. Dermatol Surg. Dec 2006;32(12):1535. [Medline].

  24. Narins RS, Beer K. Liquid injectable silicone: a review of its history, immunology, technical considerations, complications, and potential. Plast Reconstr Surg. Sep 2006;118(3 Suppl):77S-84S. [Medline].

  25. Richards RN. Calluses, corns, and shoes. Semin Dermatol. Jun 1991;10(2):112-4. [Medline].

  26. Dockery GL, Nilson RZ. Intralesional injections. Clin Podiatr Med Surg. Jul 1986;3(3):473-85. [Medline].

 
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Hard corn on the lateral surface of fifth toe. Courtesy of James K. DeOrio, MD.
Hard corn over the proximal interphalangeal joint of second toe. Courtesy of James K. DeOrio, MD.
Calluses on the palmar surface of the hands of a body builder. Courtesy of James K. DeOrio, MD.
 
 
 
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