hands, knees, and soles of the feet. This is caused by an accelerated growth of
epidermal cells—more than five times its normal rate. Less than 3% of the pop-
ulation of the United States is affected by psoriasis. More caucasians are affected
than African-Americans and onset occurs between 10 and 30 years old.
Patients who have psoriasis are treated with antipsoriatic medications that
loosen erythematous papules and plaques. However, patients usually experience
periods of exacerbation and remission.
Psoriasis scales are loosened with keratolytics (salicylic acid, sulfur). Topical
glucocorticoids are used for mild psoriasis. Other topical preparations that are
effective for psoriasis include anthralin (Anthra-Derm, Lasan) and coal tar
(Estar, PsoriGel).
Applications of 1% anthralin may cause erythema to occur and can stain
clothing, skin, and hair. Coal tar products are available in shampoos, lotions, and
creams. However, they have an unpleasant odor and can cause burning and
stinging. Systemic toxicity does not occur with anthralin and coal tar.
Calcipotriene (Dovonex), a synthetic vitamin D 3 derivative, is used to sup-
press cell proliferation, but it may cause local irritation, hypercalciuria, and
hypercalcemia (increased calcium levels in urine).
Methotrexate, an anti-cancer drug, slows cellular growth and is prescribed to
decrease the acceleration of epidermal cell growth in severe psoriasis. Etretinate
(Tegison) is used for severe pustular psoriasis when other medications have
failed. Etretinate has an anti-inflammatory effect and inhibits keratinization and
proliferation of the epithelial cells.
Ultraviolet A (UVA) may also be used to suppress mitotic (cell division)
activity. Photochemotherapy, a combination of ultraviolet radiation with a pso-
ralen derivative, methoxsalen (photosensitive drug), is used to decrease prolif-
eration of epidermal cells. This is called psoralen and ultraviolet A (PUVA) and
permits lower doses of drug and ultraviolet A to be used.
See Antipsoriatic in the Appendix. Detailed tables show doses, recommenda-
tions, expectations, side effects, contraindications, and more; available on the
book’s Web site (see URL in Appendix).WARTS
A wart is a benign lesion characterized as a hard, horny nodule that may appear
anywhere on the body, but particularly on the hands and feet. Warts are removed
by freezing, electrodesiccation, or surgical excision.
Salicyclic acid, podophyllum resin, and cantharidin are three medications com-
monly used to remove warts. Salicylic acid promotes desquamation. However, sal-
icylic acid is also absorbed through the skin and can result in salicylism (toxicity).(^376) CHAPTER 20 Skin Disorders