Ten subjects with plaque-type psoriasis (5 females, 5 males, median age 47, range 20-71 years, median psoriasis area and severity index [PASI] score = 15.5, range 8.1-23.0) were observed before (week 0) and at the second and sixth week after starting treatment (PASI = 10.5, range 7.8-14.6; PASI = 8.5, range 1.6-11.6, respectively). At each of these times, the patients were evaluated for both lesional and unlesional skin corneometry and serum E-selectin values, previously shown to be increased in psoriatic subjects. At time 0, both the corneometry and the E-selectin values were significantly correlated with the PASI, infiltration and desquamation scores. As expected, the corneometry was statistically higher in the unlesional than in the lesional areas (p < 0.001). After therapy, the lesion improvement was related both to the PASI scores and E-selectin level decreases (from median levels of 15.5 to 8.5 and from 18 to 13.2 ng/ml, respectively, p < 0.05) as well as to the corneometric level increases (from a median value of 34.5 to 42, p < 0.05). Considering the data obtained at all of these times, significant correlations were found between the PASI scores, lesional skin corneometry and serum E-selectin levels. In conclusion, lesional corneometry seems to represent an objective alternative method for reliably monitoring psoriatic patients.