Pigmentation: selective photothermolysis or non-specific skin necrosis using different intense pulsed light systems?

Abstract

Background and objective: This study considers end point tissue responses and side effects to determine whether ‘square pulse’ IPL is more or less effective than the traditional IPL. Supporting histological data and computational modelling results are provided. It provides guidance for IPL users unfamiliar with constant spectrum IPL devices and redirects attention to treatment end points. Materials and methods: Twenty subjects of Fitzpatrick Skin Types I–III, presenting with various epidermal pigmented lesions, were treated 1–3 times with two different IPLs. Coupling gel was used and firm pressure was applied to exclude blood from the treatment area. Immediate and post-treatment side effects, degree of discomfort and end results at fourteen and thirty days were evaluated by professional observation, digital photography and a patient questionnaire. Results: Both IPLs showed a mean clearance of over 80% after 1–3 treatments but the free discharge IPL demonstrated a greater side effect profile with a higher incidence of ulceration, crusting and erythema. Conclusions: Clinical observation and mathematical modelling suggests that the square pulse, partial discharge IPL system may provide the IPL operator with greater control over the coagulation of pigment and is therefore the more efficient device for effective pigment lightening with fewer side effects.

Key Words::

• coagulation
• lasers and light sources (constant spectrum)
• selective photothermolysis
• tissue necrosis

Declaration of interest: The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.

Godfrey Town receives travel expenses and salary from CyDen Ltd, UK, has an equity position with GCG Healthcare Ltd, UK, and receives consultancy fees from UNILEVER, Trumball, USA. Caerwyn Ash is a PhD graduate at University of Wales and receives travel grants from the university. He also received salary from CyDen Ltd and has a minor stock holding in the company.