The rationale for the use of vitamin D derivatives in the treatment of psoriasis is based on the observation that patients with hypocalcemia often develop various forms of psoriasis, most notably the pustular form. In one case, a patient who had undergone thyroidectomy developed repeated flares of pustular psoriasis after decreases were made in her dosage of ergocalciferol (Vitamin D 2 ); each episode was related to severe hypocalcemia and resolved after her serum calcium levels normalized. 14 Another patient with osteoporosis experienced dramatic improvement in severe psoriasis after receiving an oral form of vitamin D. 15 This finding, along with the discovery that the bioactive form of 1,25-dihydroxycholecalciferol has been shown to inhibit keratinocyte proliferation and promote keratinocyte differentiation, 16 has led to the development of vitamin D analogs for the treatment of psoriasis.
Corticosteroids are generally teratogenic in laboratory animals when administered systemical-ly at relatively low dosage levels. The more potent corticosteroids have been shown to be ter-atogenic after dermal application in laboratory animals. There are no adequate and well-controlled studies in pregnant women on teratogenic effects from topically applied corticosteroids. Therefore, topical corticosteroids should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Drugs of this class should not be used extensively on pregnant patients, in large amounts, or for prolonged periods of time.
Many hemangiomas will leave behind a combination of redundant stretched skin and bulky subcutaneous fibrofatty tissue after the vessels have involuted. These patients are the safest candidates for surgical debulking because there are few if any residual vessels, and it is much easier to judge how much soft tissue to leave behind. A smooth surgical scar is generally superior to a protruding mound or loose redundant skin. In most cases, however, patients and their parents will be reluctant to wait until complete shrinkage because the waiting period will extend into the early school years.