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Clavus Workup

  • Author: Nanette B Silverberg, MD; Chief Editor: William D James, MD  more...
Updated: Aug 22, 2016

Laboratory Studies

Blood glucose testing is required when paring of a clavus reveals an ulcer or when diabetes mellitus is suspected. In the setting of neuropathy, neuroborreliosis should be considered, and testing is performed with Lyme titers. Rheumatoid factor testing for deformities consistent with rheumatoid arthritis may be indicated. Also see Lyme Disease and Rheumatoid Arthritis.


Imaging Studies

Imaging studies are required in clavus patients only to detect underlying bony abnormalities. Studies may include radiography and, occasionally, CT scanning of the affected area with bone window settings.[35]


Other Tests

Pedobarographic studies are pressure assessments that may be used in clavus patients to detect an altered distribution of foot pressure.



Biopsy of the lesions reveals hyperkeratosis and, occasionally, mucin deposition. Paring of the clavus can relieve pressure temporarily. Biopsy may be helpful in considering some of the other differential diagnoses, such as warts. Additionally, Biopsy can be performed to differentiate clavus from porokeratosis palmoplantaris et disseminatum or discreta. These disorders occurred in those aged 20-40 years who have hyperkeratotic plaques on the palms and soles. Biopsy shows a cornoid lamella.


Histologic Findings

Histopathology reveals thickened stratum corneum (ie, compact orthokeratosis).

Contributor Information and Disclosures

Nanette B Silverberg, MD Clinical Professor of Dermatology, Icahn School of Medicine at Mount Sinai; Chief, Pediatric Dermatology, Mt Sinai Health Systems, Mount Sinai St Luke's-Roosevelt Hospital and Mt Sinai Beth Israel Medical Centers

Nanette B Silverberg, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Society for Pediatric Dermatology, Women's Dermatologic Society, European Society for Pediatric Dermatology, Dermatology Foundation, American Association of University Women, Pediatric Dermatology Research Alliance, Vitiligo Support International, American Academy of Pediatrics, American Medical Association, American Medical Womens Association, Phi Beta Kappa, Sigma Xi

Disclosure: Nothing to disclose.

Specialty Editor Board

David F Butler, MD Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

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

Disclosure: Nothing to disclose.

Jeffrey J Miller, MD Associate Professor of Dermatology, Pennsylvania State University College of Medicine; Staff Dermatologist, Pennsylvania State Milton S Hershey Medical Center

Jeffrey J Miller, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Society for Investigative Dermatology, Association of Professors of Dermatology, North American Hair Research Society

Disclosure: Nothing to disclose.

Chief Editor

William D James, MD Paul R Gross Professor of Dermatology, Vice-Chairman, Residency Program Director, Department of Dermatology, University of Pennsylvania School of Medicine

William D James, MD is a member of the following medical societies: American Academy of Dermatology, Society for Investigative Dermatology

Disclosure: Nothing to disclose.


Smeena Khan, MD Private Practice, Adult and Pediatric Dermatology Associates

Smeena Khan, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Dermatology

Disclosure: Nothing to disclose.

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Screwdriver operator's callus (ie, clavus).
Table. Clavus Formation Named for Specific Etiology or Location
Vernacular Term Location Association
Jeweler's callus, cherry pitter's thumb,[4] cameo engraver's corn[5] ThumbDigital changes, including callosities related to repetitive use of fine jeweler's instruments, which also may be seen with the use of cherry-pitting tools
Weight lifter's callus[6] Callosities over the palmar metacarpophalangeal jointsCaused by the friction of weight-lifting apparatus (This also may be seen in athletes who participate in crew.)
Prayer callus[7, 8] Callosity on the foreheadFrom kneeling prayer with the hands on the forehead
Cigarette lighter's thumb[9] Hyperkeratosis of the radial aspect of the thumbCaused by excessive cigarette lighter flicking
Knuckle pads[10] Hyperkeratosis over the knucklesCaused by boxing training
Russell sign[11] Callosities of the dorsum of the hand over the metacarpophalangeal and interphalangeal jointsCaused by the friction involved with self-induced emesis in bulimia nervosa
Screwdriver operator's clavus[12] Palmar surface of the handOccurs at the site of contact with a screwdriver handle
Spine bumpsHyperkeratosis over the spinal columnCaused by dancing with spinning on one's back
Hairdresser's handFirst finger on dominant handCallus formation at the site of friction caused by scissors around the first finger on the dominant hand
Sucking calluses[13] Lip, hand, or foot of a newbornCallus formation at the site of an area of suction on the lip, hand, or foot of a newborn
Vamp disease[14] FeetClavus formation due to wearing tight high-heeled shoes
Muay Thai kickboxers[15] FeetCallosities on the forefoot (77.5%), on the plantar first metatarsal (55.3%), and on the big toe (33.3%)
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