Ke. Mckenna et Rs. Stern, PHOTOSENSITIVITY ASSOCIATED WITH COMBINED UV-B AND CALCIPOTRIENE THERAPY, Archives of dermatology, 131(11), 1995, pp. 1305-1307
Background: Ultraviolet B phototherapy is an effective agent for the t
reatment of psoriasis; its most frequent: acute side effect is burning
of the skin. It has been combined with various other topical or syste
mic agents to augment therapeutic effect. Recently, UV-B therapy has b
een used with calcipotriene ointment (Dovonex, Westwood-Squibb, Buffal
o, NY), a new vitamin D analogue. Observations: We report four cases o
f chronic plaque psoriasis that developed in patients who used UV-B ph
ototherapy for a substantial period without ill effects and in whom ph
otosensitivity reactions within psoriatic plaques developed after calc
ipotriene ointment was added, without changes in their UV-B dosage or
frequency of treatment. The time from starting calcipotriene therapy t
o the development of photosensitivity ranged from 4 to 28 days, and th
e number of UV-B exposures during this period varied between one and 1
2 treatments. The mean UV-B dose at burning was 1114 mJ/cm(2). Twenty-
two patients had used calcipotriene in combination with UV-B therapy o
f a total of 103 UV-B-treated patients during the period when the adve
rse events occurred. Half these patients started calcipotriene therapy
prior to starting treatment with UV-B. However, cases of photosensiti
vity occurred only in the remaining half of the patients in whom calci
potriene therapy was added during UV-B therapy. Combined therapy was a
ble to be continued or resumed in two patients by reduction of the UV-
B dose. In three cases, phototesting confirmed greater photosensitivit
y to calcipotriene-treated skin than to skin to which hydrated petrola
tum was applied. Conclusions: Calcipotriene ointment should be introdu
ced with caution in patients already receiving UV-B phototherapy, part
icularly those receiving high doses of UV-B. The mechanism of this pho
tosensitivity reaction is unknown. This increased sensitivity to UV-B
may be a result of the effect of calcipotriene on stratum corneum thic
kness, epidermal melanization, a result of its effect on the inflammat
ory reaction to UV-B irradiation, or, possibly, because it is a photot
oxic agent.