Spectrophotometric intracutaneous analysis as an early non-invasive predictor of efficacy in the phototherapy of psoriasis

Phototherapy is generally effective for psoriasis but individual responsiveness and optimal treatment duration for disease clearance are unpredictable. However, easy, rapid and non-invasive plaque assessment by spectrophotometric intracutaneous analysis (SIAscopy), a novel multispectral skin imaging technique, may now make prediction feasible. The early prediction of psoriatic plaque clearance during phototherapy by SIAscopy. Sixteen psoriatic plaques in 10 psoriasis patients were serially assessed SIAscopically during phototherapy for punctate dots representing the dilated papillary dermal blood vessels characteristic of active psoriasis, and the results compared with the clinical findings. All plaques showing full SIAscopic clearance at early follow-up also showed complete or almost complete clinical clearance, and remained the same thereafter. All showing no SIAscopic clearance at early follow-up showed at most partial clinical clearance, and also remained the same thereafter. All showing only partial SIAscopic clearance at early follow-up also showed just partial clinical clearance, but then generally progressed to full SIAscopic and clinical clearance. SIAscopy of psoriatic plaques at early follow-up during patient phototherapy enables good prediction of likely later clinical clearance, thereby potentially avoiding unnecessary further treatment. A larger confirmatory study is now needed.