eMedicine Specialties > Dermatology > Diseases of the Dermis

Knuckle Pads

Author: Cheryl J Barnes, MD, Dermatologist, McIntosh Clinic, PC
Coauthor(s): Loretta Davis, MD, Professor, Department of Internal Medicine, Division of Dermatology, Medical College of Georgia
Contributor Information and Disclosures

Updated: Jun 12, 2009

Introduction

Background

Knuckle pads are benign, asymptomatic, well-circumscribed, smooth, firm, skin-colored papules, nodules, or plaques, located in the skin over the dorsal aspects of the metacarpophalangeal (MCP) and interphalangeal (IP) joints. A history of repetitive trauma related to sports or occupation is often present.

Garrod first described knuckle pads in the medical literature in 1893,1 but knuckle pads have been observed since the Renaissance era. Allison et al shows a photo of Michelangelo's statue of David displaying knuckle pads (Florence, Italy) as well as his statue of Moses (Rome, Italy), Victory (Florence, Italy), and Giuliano de Medici (Rome, Italy).2 The name knuckle pad seems to be a misnomer because in most reported cases, lesions occur over the proximal interphalangeal (PIP) joint, not over the knuckles.

Pathophysiology

Knuckle pads may be idiopathic, genetic, acquired as a response to repetitive trauma, or associated with several other acquired conditions.

Frequency

United States

Knuckle pads are a common occurrence. Measurement of prevalence of knuckle pads is difficult because patients are asymptomatic and do not seek medical attention for them.

International

Knuckle pads were noted in about 9% of subjects in one survey. Patients with Dupuytren contracture are 4 times as likely as the general population to have knuckle pads.

Mortality/Morbidity

Little morbidity is associated with knuckle pads. Patients typically are asymptomatic, but some patients experience pain and difficulty with hand functioning, including writing, as a result of their condition. Cosmetic issues drive most patients to seek attention for knuckle pads.

Race

No racial predilection is associated with knuckle pads.

Sex

Prevalence of knuckle pads is equal for men and women. Even in the presence of Dupuytren contracture, the prevalence of knuckle pads remains equal.

Age

Knuckle pads can present at any age. They have been reported in young children who bite and suck their fingers.3 More commonly, knuckle pads are observed in adults older than 40 years.

Clinical

History

Most patients are asymptomatic. Firm skin-colored papules appear sequentially in multiple sites overlying the MCP and PIP joints of the hands. Individual lesions enlarge into well-defined plaques and nodules. Though complaints of pain or functional impairment of fine motor skills are rare, cosmetic concerns frequently are raised. A history of repetitive trauma often is elicited.

Physical

Knuckle pads are well-circumscribed firm dermal papules, nodules, or plaques approximately 0.5-3 cm in size, located on the extensor aspect of the PIP or MCP joints. If subjected to repetitive injury, knuckle pads may develop over virtually any bony prominence, but the PIP joint area is affected most commonly.

Knuckle pad over the proximal interphalangeal joi...

Knuckle pad over the proximal interphalangeal joint.

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Knuckle pad over the proximal interphalangeal joi...

Knuckle pad over the proximal interphalangeal joint.



Multiple knuckle pads on various joints of the ha...

Multiple knuckle pads on various joints of the hand.

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Multiple knuckle pads on various joints of the ha...

Multiple knuckle pads on various joints of the hand.

Causes

Most knuckle pads are idiopathic or are related to repetitive trauma. Work-related trauma with repeated motions or rubbing of the PIP joints or knuckles, as seen in live-chicken hangers in a poultry processing plant,4 has been reported. Athletes, such as boxers, have been known to traumatize their knuckles and fingers in a repetitive fashion, causing knuckle pads.5,6 Surfers have developed "surfer's knots" from repeated friction between the surfboard and the body part exposed to the repeated trauma.7 A few cases involving the toes have been reported; these cases were thought to be sequelae of ill-fitting shoes.

Psychologically disturbed children who bite and suck their fingers cause thickenings that resemble knuckle pads to occur in the skin in the traumatized areas. Patients with bulimia who use their knuckles or fingers to induce emesis sometimes develop fibrotic papules resembling knuckle pads.8

Some cases of knuckle pads are familial. They have been associated with the autosomal dominant palmoplantar keratoderma with and without ichthyosis vulgaris. Knuckle pads were found in 2 families with autosomal dominant sensorineural deafness and leukonychia (Bart-Pumphrey syndrome).9 Knuckle pads also have been reported in pseudoxanthoma elasticum.10,11 Dupuytren disease, Peyronie disease, and Ledderhose disease are at times observed together, and the triad may be associated with knuckle pads.12,13,14 Knuckle pads also have been associated with esophageal cancer,15 hyperkeratosis,16 oral leukoplakia,15 and clubbed fingers.17 One case report links phenytoin with polyfibromatous syndrome.18

More on Knuckle Pads

Overview: Knuckle Pads
Differential Diagnoses & Workup: Knuckle Pads
Treatment & Medication: Knuckle Pads
Follow-up: Knuckle Pads
Multimedia: Knuckle Pads
References
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References

  1. Garrod AE. On an unusual form of nodule upon joints of the fingers. St. Bartholomew's Hosp Rep. 1893;29:157-161.

  2. Allison JR Jr, Allison JR Sr. Knuckle pads. Arch Dermatol. Mar 1966;93(3):311-6. [Medline].

  3. Paller AS, Hebert AA. Knuckle pads in children. Am J Dis Child. Sep 1986;140(9):915-7. [Medline].

  4. Richards TB, Gamble JF, Castellan RM, Mathias CG. Knuckle pads in live-chicken hangers. Contact Dermatitis. Jul 1987;17(1):13-6. [Medline].

  5. Cohen PR, Eliezri YD, Silvers DN. Athlete's nodules. J Am Acad Dermatol. Feb 1991;24(2 Pt 1):317-8. [Medline].

  6. Kanerva L. Knuckle pads from boxing. Eur J Dermatol. Jul-Aug 1998;8(5):359-61. [Medline].

  7. Swift S. Surfers' "Knots". JAMA. Apr 19 1965;192:223-4. [Medline].

  8. Wynn DR, Martin MJ. A physical sign of bulimia. Mayo Clin Proc. Oct 1984;59(10):722. [Medline].

  9. Bart RS, Pumphrey RE. Knuckle pads, leukonychia and deafness. A dominantly inherited syndrome. N Engl J Med. Jan 26 1967;276(4):202-7. [Medline].

  10. Stankler L. Pseudoxanthoma elasticum with a knuckle pad on the thumb. Acta Derm Venereol. 1967;47(4):263-6. [Medline].

  11. Codispoti A, Colombo E, Zocchi L, et al. Knuckle pads, in an epidermal palmoplantar keratoderma patient with Keratin 9 R163W transgrediens expression. Eur J Dermatol. Mar-Apr 2009;19(2):114-8. [Medline].

  12. Lagier R, Meinecke R. Pathology of "knuckle pads". Study of four cases. Virchows Arch A Pathol Anat Histol. 1975;365(3):185-91. [Medline].

  13. Mikkelsen OA. Knuckle pads in Dupuytren's disease. Hand. Oct 1977;9(3):301-5. [Medline].

  14. Wooldridge WE. Four related fibrosing diseases. When you find one, look for another. Postgrad Med. Aug 1988;84(2):269-71, 274. [Medline].

  15. Ritter SB, Petersen G. Esophageal cancer, hyperkeratosis, and oral leukoplakia. Occurrence in a 25-year-old woman. JAMA. Apr 19 1976;235(16):1723. [Medline].

  16. Leonard NJ, Krol AL, Bleoo S, Somerville MJ. Sensorineural hearing loss, striate palmoplantar hyperkeratosis, and knuckle pads in a patient with a novel connexin 26 (GJB2) mutation. J Med Genet. Jan 2005;42(1):e2. [Medline].

  17. Koba S, Misago N, Narisawa Y. Knuckle pads associated with clubbed fingers. J Dermatol. Dec 2007;34(12):838-40. [Medline].

  18. Pierard GE, Lapiere CM. Phenytoin dependent fibrosis in polyfibromatosis syndrome. Br J Dermatol. Mar 1979;100(3):335-41. [Medline].

  19. Glicenstein J, Costa R. [Pachydermodactyly: a report of two cases]. Chir Main. Aug 2004;23(4):205-7. [Medline].

  20. Verbov J. Letter: Pachydermodactyly: a variant of the true knuckle pad. Arch Dermatol. Apr 1975;111(4):524. [Medline].

  21. Weiss E, Amini S. A novel treatment for knuckle pads with intralesional Fluorouracil. Arch Dermatol. Nov 2007;143(11):1458-60. [Medline].

  22. Quinn KJ. Silicone gel in scar treatment. Burns Incl Therm Inj. Oct 1987;13 Suppl:S33-40. [Medline].

  23. Addison A. Knuckle pads causing extensor tendon tethering. J Bone Joint Surg Br. Jan 1984;66(1):128-30. [Medline].

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Further Reading

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Keywords

knuckle pad, halodermia, subcutaneous fibroma, keratosis supracapitularis, discrete keratoderma

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Contributor Information and Disclosures

Author

Cheryl J Barnes, MD, Dermatologist, McIntosh Clinic, PC
Cheryl J Barnes, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

Coauthor(s)

Loretta Davis, MD, Professor, Department of Internal Medicine, Division of Dermatology, Medical College of Georgia
Loretta Davis, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

Medical Editor

Gregory J Raugi, MD, PhD, Professor, Department of Internal Medicine, Division of Dermatology, University of Washington at Seattle; Chief, Dermatology Section, Primary and Specialty Care Service, Veterans Administration Medical Center of Seattle
Gregory J Raugi, MD, PhD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

Pharmacy Editor

Michael J Wells, MD, Associate Professor, Department of Dermatology, Texas Tech University Health Sciences Center
Michael J Wells, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, and Texas Medical Association
Disclosure: Nothing to disclose.

Managing Editor

Edward F Chan, MD, Clinical Assistant Professor, Department of Dermatology, University of Pennsylvania School of Medicine
Edward F Chan, MD is a member of the following medical societies: American Academy of Dermatology, American Society of Dermatopathology, and Society for Investigative Dermatology
Disclosure: Nothing to disclose.

CME Editor

Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University
Catherine 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, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

 
 
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