Medication Summary
The goals of pharmacotherapy are to reduce morbidity and to prevent complications.
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 triamcinolone and topical vitamin A acid compounds also may reduce localized hyperkeratosis. Triamcinolone 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.
A combination product to be applied by physicians consisting of 1% cantharidin, a vesicant, mixed with 30% salicylic acid and 5% podophyllin has been described as effective for most people after just one session. [70]
Keratolytic agents
Class Summary
These agents cause the 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).
Salicylic acid topical (Clear Away, Compound W, Dr. Scholl's Corn Removers)
Topical salicylic acid is a keratolytic, bacteriostatic, and fungistatic agent. Its main clinical use is as a keratolytic agent and as an agent that increases the percutaneous absorption of combined drugs by removing the stratum corneum. The keratolytic activity results from solubilization of the intercellular ground substance in the stratum corneum and shedding of the scales, which are bound by it.
Salicylic acid topical can be compounded in petrolatum at any percentage and is usually used at 5-20%, beginning with a lower percentage. It can be purchased over the counter as a liquid or pad preparation, ranging from 17-40% (multiple companies make these). It can be irritating or cause blistering.
Ammonium lactate (AmLactin, Lac-Hydrin, Lactinol)
Ammonium lactate may loosen the adhesion of the keratinocytes in the stratum corneum, thereby thinning the skin. Ammonium lactate provides beneficial effects on dry skin and severe hyperkeratotic conditions. It is indicated for moisturizing and softening dry, scaly skin.
Urea (Aquadrate, Calmurid, Carmol, Nutraplus)
Urea is a a keratolytic, bacteriostatic, bactericidal, and fungistatic agent. It is topical treatment for dry skin and ichthyosis and is also used as a skin moisturizer. Urea promotes the hydration and removal of excess keratin in conditions of hyperkeratosis.
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 (Aristospan, Kenalog IV, Trivaris)
An 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.
Retinoids
Class Summary
These agents are not specifically approved for use in corn (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 (Atralin, Avita, Refissa)
Tretinoin topical inhibits microcomedo formation and eliminates lesions. It makes keratinocytes in sebaceous follicles less adherent and easier to remove. It is available as 0.025%, 0.05%, and 0.1% creams and 0.01% and 0.025% gels.
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Hard corn on the lateral surface of fifth toe. Courtesy of James K. DeOrio, MD.
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Hard corn over the proximal interphalangeal joint of second toe. Courtesy of James K. DeOrio, MD.
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Calluses on the palmar surface of the hands of a body builder. Courtesy of James K. DeOrio, MD.
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Screwdriver operator's callus (ie, clavus).
Tables
Vernacular Term |
Location |
Association |
Jeweler's callus, cherry pitter's thumb, [16] cameo engraver's corn [17] |
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 [18] |
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.) |
Callosity on the forehead |
From kneeling prayer with the hands on the forehead |
|
Cigarette lighter's thumb [21] |
Hyperkeratosis of the radial aspect of the thumb |
Caused by excessive cigarette lighter flicking |
Knuckle pads [22] |
Hyperkeratosis over the knuckles |
Caused by boxing training |
Russell sign [23] |
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 [24] |
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 [25] |
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 [26] |
Feet |
Clavus formation due to wearing tight high-heeled shoes |
Muay Thai kickboxers [27] |
Feet |
Callosities on the forefoot (77.5%), on the plantar first metatarsal (55.3%), and on the big toe (33.3%) |
