The glucocorticoid is stated in several references not to be porphyrinogenic. Probably only insignificant systemic exposure.

Strong glucocorticoid salve, momethasone 0.001%, used in severe plaque psoriasis. Glucocorticoid: South African list: use. Kalman, Bonkovsky: believed to be safe. The Merck Manual: use. Moore MR, Hift RJ: Drugs in acute porphyria. Cell Mol Biol 43:89, 1997: safe. Tschudy DP, Lamon JM: Porphyrin metabolism and the Porphyrias in Bondy BK, Rosenberg LE (eds): Duncan’s Diseases of Metabolism, Philadelphia, WB Saunders 1980, p 939: safe. .