Medication Summary
Debridement may be enhanced with the use of keratolytic agents, such as ureas, alpha-hydroxy acid (eg, glycolic, malic, or lactic acid), or beta-hydroxy acid (eg, salicylic acid). The use of these agents is not recommended in pregnant women and young children. Most salicylic acid compounds are 10-17%. High concentrations of salicylic acid (eg, 40%) may lead to severe maceration and frank foot ulcerations in patients with diabetes. Self-adhesive pads are most effective for reducing thick lesions, whereas lotions, creams, and medicaments in petrolatum are best for maintenance. Intralesional Kenalog and topical vitamin A acid compounds also may reduce localized hyperkeratosis. Kenalog may be injected during pregnancy because of its limited absorption; however, it can lead to localized hypopigmentation. Topical vitamin A derivatives are not intended for use in women who are pregnant or intending to become pregnant because their safety ranges from category C to category X.
Keratolytics
Class Summary
These agents cause cornified epithelium to swell, soften, macerate, and then desquamate. Commonly used agents include urea, alpha-hydroxy acids (eg, lactic acid, glycolic acid), and beta-hydroxy acids (eg, salicylic acid).
Ammonium lactate (Lac-Hydrin)
May loosen the adhesion of the keratinocytes in the stratum corneum, thereby thinning the skin.
Salicylic acid topical (Compound W, Panscol, Sal-Plant)
May be compounded in petrolatum at any percentage, usually is used at 5-20%, beginning with lower percentage. Can be purchased over the counter as a liquid or pad preparation, ranging from 17-40% (multiple companies make these). Can be irritating or cause blistering.
Urea (Ureacin-40, Aquacare)
Promotes the hydration and removal of excess keratin in conditions of hyperkeratosis.
Intralesional corticosteroids
Class Summary
These drugs have anti-inflammatory properties and cause profound and varied metabolic effects. Corticosteroids modify the body's immune response to diverse stimuli.
Triamcinolone (Kenalog, Amcort)
Injectable version of triamcinolone is available in concentrations of 3-40 mg/mL. Generally, this compound is diluted to 1-4% for injection into lesions, such as a clavus.
Corticosteroids cause the skin to thin, and this beneficial side effect can be used to reduce the thickness of a clavus. However, overusage also can lighten the skin and cause atrophy.
Retinoids
Class Summary
Retinoids decrease the cohesiveness of abnormal hyperproliferative keratinocytes, and they may reduce the potential for malignant degeneration. Retinoids modulate keratinocyte differentiation.
These agents are not specifically approved for use in clavus therapy. Only tretinoin has been shown to be useful for clavus therapy in the topically applied form. These agents cause the skin to peel by loosening of keratinocyte adhesion. Irritation and discomfort are limiting adverse effects.
Tretinoin topical (Retin-A, Avita)
Inhibits microcomedo formation and eliminates lesions present. Makes keratinocytes in sebaceous follicles less adherent and easier to remove. Available as 0.025%, 0.05%, and 0.1% creams. Also available as 0.01% and 0.025% gels.
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| Vernacular Term | Location | Association |
| Jeweler's callus, cherry pitter's thumb,[4] cameo engraver's corn[5] | Thumb | Digital 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 joints | Caused 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 forehead | From kneeling prayer with the hands on the forehead |
| Cigarette lighter's thumb[9] | Hyperkeratosis of the radial aspect of the thumb | Caused by excessive cigarette lighter flicking |
| Knuckle pads[10] | Hyperkeratosis over the knuckles | Caused by boxing training |
| Russell sign[11] | Callosities of the dorsum of the hand over the metacarpophalangeal and interphalangeal joints | Caused by the friction involved with self-induced emesis in bulimia nervosa |
| Screwdriver operator's clavus[12] | Palmar surface of the hand | Occurs at the site of contact with a screwdriver handle |
| Spine bumps | Hyperkeratosis over the spinal column | Caused by dancing with spinning on one's back |
| Hairdresser's hand | First finger on dominant hand | Callus 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 newborn | Callus formation at the site of an area of suction on the lip, hand, or foot of a newborn |
| Vamp disease[14] | Feet | Clavus formation due to wearing tight high-heeled shoes |

