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Paradoxical Hypertrichosis Associated with Laser and Light Therapy for Hair Removal: A Systematic Review and
Igor Snast1,2, Ran Kaftory2, Moshe Lapidoth1,2
1Laser Unit, Division of Dermatology, Rabin Medical Center, 39 Jabotinsky St., Petah Tikva, 4941492, Israel.
American Journal of Clinical Dermatology
|May 31, 2021
Summary
Paradoxical hypertrichosis (PH) affects 3% of patients undergoing laser hair removal, primarily on the face and neck. Continued treatment may help improve this adverse effect.
Area of Science:
- Dermatology
- Aesthetic Medicine
- Medical Adverse Effects
Background:
- Paradoxical hypertrichosis (PH) is an uncommon adverse effect of laser and intense pulsed light (IPL) hair removal.
- The underlying mechanisms and precise prevalence of PH remain poorly understood.
Purpose of the Study:
- To systematically review and meta-analyze the prevalence of paradoxical hypertrichosis (PH).
- To identify risk factors associated with PH following laser or IPL hair removal.
Main Methods:
- Systematic review and meta-analysis of randomized controlled trials and cohort studies.
- Investigated PH prevalence and associated factors using meta-regression and subgroup analysis.
Main Results:
- Pooled PH prevalence was 3% across 9733 patients, predominantly in facial/neck areas (0.08% elsewhere).
- Treatment modality and inter-treatment interval did not significantly impact PH rates.
- PH showed gradual improvement with continued therapy in most cases.
Conclusions:
- Paradoxical hypertrichosis (PH) is a rare but recognized adverse effect of laser/IPL hair removal, mainly affecting the face/neck.
- Treatment modality is not a significant factor in PH development.
- Continuing treatment may be the most effective management strategy for PH.
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