Medication Summary
Although surgical treatment is the modality for keratoacanthoma, in patients with clear-cut and multiple keratoacanthomas, a number of medical alternatives have been used with success.
Antineoplastic agents (eg, topical and intralesional 5-fluorouracil, [32, 33] intralesional methotrexate, interferon alfa-2a, [35] and bleomycin) have been used with some success in treating keratoacanthomas.
Retinoidlike agents are efficacious in the treatment of keratoacanthomas with good cosmetic outcome. [36]
Antineoplastics
Class Summary
These agents are useful in patients with large or multiple tumors or tumors that are inoperable because of anatomic location or the patient's poor medical status. They also are useful for eruptive keratoacanthomas of the lower legs. Agents (eg, topical and intralesional 5-fluorouracil, intralesional MTX, interferon alfa-2a, and bleomycin) also have been used with some success in treating keratoacanthomas. When small amounts of medication are administered, the interactions and precautions listed below are less restrictive than when systemic doses are administered. As a rule, if after 4 weeks the lesion has not responded fully to medical therapy, surgical removal is indicated.
Methotrexate (Trexall, Rheumatrex)
Methotrexate is an antimetabolite that inhibits DNA synthesis and cell reproduction in malignant cells. It may suppress the immune system. Satisfactory response may be seen within 3-6 weeks following administration. A marked response may be noticed after 2 injections (1 study).
Fluorouracil (Adrucil)
Fluorouracil is a fluorinated pyrimidine antimetabolite that inhibits thymidylate synthase (TS) and interferes with RNA synthesis and function. It has some effect on DNA. It is useful in symptom palliation for patients with progressive disease.
Bleomycin
Bleomycin is a glycopeptide antibiotic that inhibits DNA synthesis. The concentration usually is 1 mg/mL and diluted further with local anesthetic.
Retinoid-like Agents
Class Summary
These agents are efficacious in the treatment of keratoacanthomas with good cosmetic outcome. They decrease sebaceous gland size and sebum production and may inhibit sebaceous gland differentiation and abnormal keratinization.
Isotretinoin (Amnesteem, Claravis, Sotret)
Isotretinoin is an oral agent that treats serious dermatologic conditions. It is a synthetic 13-cis isomer of naturally occurring tretinoin (trans-retinoic acid). Both agents are structurally related to vitamin A. Acitretin is another retinoid. However, oral retinoids are more often used in patients with multiple keratoacanthomas.
An FDA–mandated registry now in place for all individuals prescribing, dispensing, or taking isotretinoin. For more information, see iPLEDGE. The registry aims to further decrease the risks of pregnancy and other unwanted and potentially dangerous adverse effects during a course of isotretinoin therapy.
Topical Skin Products
Class Summary
The agent imiquimod has been reported to show some efficacy. However, the mechanism of action of imiquimod cream in treating keratosis is unknown.
Imiquimod (Aldara, Zyclara)
Imiquimod is an immune response modifier currently approved for the treatment of genital and perianal warts. It is capable of inducing IFN-alpha, TNF-alpha, IL-1, IL-6, and IL-8. Studies using 5% cream in mice showed significant induction of IFN-alpha at the application site occurring as early as 2 hours after treatment. At 4 hours after application, increases in IFN-alpha mRNA levels were found, indicating an increase in transcription. It is not approved by the FDA for use in hypertrophic scars and keloids.
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Keratoacanthoma (squamous cell carcinoma-keratoacanthoma or SCC-KA type) on inner canthus.
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Keratoacanthoma of the left forehead.
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Close-up view of the keratoacanthoma.
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Keratoacanthoma lesion (squamous cell carcinoma-keratoacanthoma or SCC-KA type).
