Brandt H, Mustakallio KK.
DOI: 10.2340/0001555563237240

Irritation and staining, the side effects of dithranol and related compounds have previously been studied after a single chamber-exposure. To mimic the therapeutic situation, the chamber application was repeated for 3 weeks on the uninvolved back skin of 17 psoriasis patients. In equimolar concentrations corresponding to 0.05% dithranol, dithranol caused markedly more erythema and staining than 10-propionyl dithranol and 10-butyryl dithranol, whereas 10-butyryl dithranol irritated and stained less than 10-propionyl dithranol. To reach the irritation and staining level of dithranol, a 4-fold higher concentration of 10-butyryl dithranol was required. During the first week the irritation culminated, declining later despite repeated applications, possibly because of exhaustion of anthrone-induced inflammatory mediators.