Trends in Paradoxical Hypertrichosis as a Result of Energy-Based Hair Removal Devices

Abstract

Background

Laser hair removal has been regarded as a relatively safe and effective treatment for the removal of unwanted body hair. While there are a variety of reported side effects like post-inflammatory hyperpigmentation or erythema, a rare and underreported complication is paradoxical hypertrichosis (PH). PH involves the unexpected increase of hair in or near the treatment area following laser hair removal. The mechanism behind this phenomenon is not fully understood but is important to address to improve treatment outcomes and minimize the occurrence of PH.

Objective

This paper aims to consolidate and analyze literature pertaining to PH as a side effect resulting from laser hair removal (LHR), focusing on identifying commonalities and trends.

Materials and Methods

A comprehensive literature search was conducted utilizing the PubMed database, employing keywords such as “laser paradoxical effect” and “paradoxical hypertrichosis.” The gathered findings were synthesized and are presented in this review.

Results

The Alexandrite and Intense Pulsed Light (IPL) lasers are frequently associated with inducing PH. PH predominantly manifests in facial and neck regions, with sporadic occurrences on other body areas, notably the upper arms and periareolar region. Patients with darker skin tones, particularly Fitzpatrick Skin Types III−VI, and those with hormonal imbalances such as polycystic ovarian syndrome (PCOS), are more predisposed to experiencing PH after LHR. Proposed preventive measures include sun protection and avoiding shaving before LHR sessions. Continuation of LHR treatments on affected areas is the standard approach for treating PH.

Conclusion

PH, although rare, poses a tangible side effect of LHR, occurring in about 3% of patients. The literature highlights specific regions of the body and laser types associated with PH, alongside potential patient predispositions. Further research is warranted to elucidate preventive strategies and enhance patient satisfaction and trust in LHR procedures.