• #4. Possible Side Effects of Photoepilation


    Since the clinical approval by FDA in 1995, photoepilation has been widely used as a very common procedure in cosmedic dermatology. Lasers used for this purpose include 694nm Ruby Laser, 755nm Alexandrite Laser, 800-810nm Diode Laser, 1064nm Neodymium:Yttrium-Aluminium Garnet Laser and IPLs emitting 590-1200nm.¹ Because these lasers are easy to use and associated with less side effects than other lasers, clinicians often perform the procedure just following the manual preset for each device, without much worry. However, my recent encounter with a patient who had an unexpected scar on the forehead from photoepilation to beautify the hairline made me reconsider the possible side effects of photoepilation.


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    A 22-year-old female patient visited the clinic for a scar developed after receiving photoepilation – she could not remember the type of laser – 2 months ago to broaden her forehead (Fig. 1). She had erythema and edema around the treated hair follicles after the second procedure of photoepilation. She contacted the doctor who performed the procedure, but was only heard that it’s a typical thing to happen after a laser therapy and could not receive any proper treatment. She was prescribed with an antiscarring cream for residual erythema and hypopigmented scar, and is currently under follow-up with recommendation to undergo a scar treatment once the erythema is subsided.


    Fig 1. There is residual erythema with hypopigmented scar along the hairline. Thin hairs left from unfinished photoepilation can be observed below the scar.


    Therapeutic Mechanism of Photoepilation

    Photoepilation is different from other laser therapies for tattoo or vasodilation, which aims at removing target chromophores. Visible red light spectrum and wavelengths close to the far-infrared region penetrates to the dermis and are absorbed by melanin in hair follicles in the dermis.² Melanin in the hair follicle absorbs the irradiated energy and acts as a mediator of heat dissipation to the bulge area, where stem cells are suspected to be present in. Because melanins are present in the substrate of hair follicle during the anagen phase, hair removal procedure is only effective during the anagen phase.


    Possible Side Effects after Photoepilation

    Chromophores that absorb laser light are melanins, which are also present in the epidermis. In order to prevent any unwanted side effect from a laser therapy, the epidermis should be always protected because the laser can be absorbed in the melanin present in the epidermis as well. To prevent epidermal melanin from being damaged by laser therapy, various methods to cool down the epidermis can be applied and a pulse width longer than the Thermal Relaxation Time of the epidermis can be used so that heat energy can selectively damage the hair follicles.
    Common postprocedural side effects, including temporary erythema, perifollicular edema, pain, folliculitis, hyperpigmentation or hypopigmentation, eschar, bruise and ulcer, are typically associated with the injury of the epidermis, and may leave a scar in severe cases. People with relatively dark skin, including Asians and black people, are more susceptible to these side effects.
    Other than the side effects of the epidermis, a case of reticulate erythema after hair removal from the arms and legs has been reported⁵, which is known to increase after hair removal in patients with a history of chilblain or angiostomy on the limbs. Careful history taking is essential before a procedure in these sites Reticulate erythema after photoepilation has been reported not to disappear and show clinical improvement only slightly.⁵ Among unusual side effects after photoepilation is a paradoxical reaction of more hair growing around the target area. These cases have been reported after hair removal with IPL,⁶ and most of the patients had polycystic ovary syndrome.
    Before hair removal in patients with acne, irregular menstruation or excessive sebum secretion on the face – representative clinical pattern of polycystic ovary syndrome – the patient should be reminded of such a risk before the procedure.
    This paradoxical reaction may not be developed until receiving repeated procedures or 2-6 months after the last procedure.


    Discussion on our Case

    The scar on the forehead in our patient may be left because she could not receive a proper treatment immediately after the emergence of the side effect. Some doctors do not check whether erythema or other side effects are present or not after a procedure, thinking that side effects are rare after photoepilation, but they should confirm it and provide proper treatments. Our patient wanted to remove the hair below the scar as well, but I recommended her to postpone it until after the scar treatment.
    Although still controversial, a lot of studies have reported that hair removal may delay wound recovery in the same area.² When treating a scar after photoepilation, it would be wise to wait until the scar is mitigated before starting to remove the residual hair, regardless of how unattractive it may seem for some time.
    Photoepilation is not as simple as shaving or hair removal creams. Because it is closely related to the physiology of the hair, understanding of the hair, as well as theoretical knowledge on laser, should be preceded before conducting a procedure.



    1. Haedersdal. M. Evidence based review of hair removal using lasers and light sources. J Eur Acad Derm Venereol 2006;20:9~20.
    2. Sellhyer K. Mechanisms of laser hair removal: could persistent photoepilation induce vitiligo or defect s in wound repair? Derm Surg 2007;33:1055~1065.
    3. Breadon JY, Barnes CA. Comparison of adverse events of laser and light assisted hair removal systems in skin types IV-VI. J Drugs Dermatol 2007;6:40~46.
    4. Haedersdal M, Gotzsche PC. Laser and photoepilation for unwanted hair growth. Cochrane Database Syst Rev 2006;18:CD004684.
    5. Lapidoth M, Shafirstein G, Ben Amitai D et al, Reticulate erythema following diode laser assisted
    hair removal: a new side effect of a common procedure. J Am Acad Dermatol 2004;51:774~777.
    6. Moreno-Arias G, Castelo-Branco C, Ferrando J. Paradoxical effect after IPL photoepilation. Derm Surg 2002;28:1013-1016.


    -The End-


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