Epidermal thickness (ET) has been suggested
as a surrogate measure of psoriasis severity. Optical coherence
tomography (OCT) is a recent imaging technology
that provides real-time skin images to a depth of 1.8 mm
with a micrometre resolution. OCT may provide an accurate
in vivo measure of ET. It is, therefore, speculated that
OCT may be used in the assessment of psoriasis vulgaris. A
total of 23 patients with psoriasis vulgaris were systematically
evaluated by OCT imaging and skin biopsy during
treatment. Biopsies were graded for disease severity, and
additional evaluation was done by the physician via psoriasis
area and severity index (PASI) score, and by the patient
through measures such as self-administered PASI, psoriasis
life stress inventory index and dermatology life quality
index. ET was calculated from OCT images. In comparison
to normal skin, psoriasis appeared with a more irregular
surface with a stronger entrance signal, a serrated dermoepidermal
junction was found and a less signal intensity in
the dermis as shown in OCT images. ET measured in
untreated plaques was thicker reXecting epidermal hyperproliferation
and inXammation. The changes were signiWcantly
correlated with the biopsy grading (r2 = 0.41,
p = 0.001) and ET signiWcantly decreased with treatment
(p = 0.0001). ET correlated signiWcantly with self-reported
measures of disease severity, but not with physicianassessed
global PASI. The data suggest that OCT may be
used to measure ET in psoriasis and the measurements correlate
with several other parameters of disease severity.
This implies that OCT assessment of psoriatic plaques may
provide a useful method for non-invasive in vivo method to
follow the evolution of psoriasis lesions.