McCoy, 1999  Title: Histological study of hair follicles
treated with a 3-msec pulsed ruby laser.
Authors: McCoy S, Evans A, James C
Journal: Lasers Surg Med 1999;24(2):142-50
PMID: 10100652, UI: 99198751
Affiliated institution: The Laser,
Skin and Vein Clinic, North Adelaide, South Australia, Australia.
suemccoy@senet.com.au
BACKGROUND AND OBJECTIVE: Ruby laser energy at 694
mn is moderately absorbed by melanin and minimally absorbed by
other skin chromophores. This property and its depth of penetration
into dermis permit absorption into pigmented hair follicles, thus
making it suited to photothermolysis of these appendages. Clinical
reports of the efficacy of such lasers for removal of unwanted
hair are emerging in large numbers, but scientific data regarding
the exact mechanism of action is still lacking. This study aims
to evaluate and define further the histological responses of hair
follicles to 3-msec pulsed ruby laser light.
STUDY DESIGN/MATERIALS AND METHODS: Twenty-four
patients with brown or black axillary or groin hair were treated
with a 3-msec ruby laser at fluences from 10 to 40 J/cm2 on one,
two, or three occasions. Biopsies were taken at various intervals
from immediately to 8 weeks after treatments. Biopsies were fixed
and stained with either nitroblue tetrazolium chloride or hematoxylin
and eosin for histological examination.
RESULTS: One treatment induced changes typical of
catagen followed by telogen at all fluences. The papillae always
remained viable. Two and three treatments resulted in atypical
telogen, with infundibular dilatation and plugging, and marked
proliferation of the stem outer sheath. New anagen follicles were
evident even after three treatments at 12- and then 8-week intervals
and were biopsied 6 weeks later, but there were no hairs extending
to or through the epidermis.
CONCLUSION: There was no evidence of permanent follicle
death after one ruby laser treatment. However, despite evidence
of persistence of follicular elements after two and three treatments,
it is possible that laser-induced damage to the isthmus and upper
stem may interfere with the interaction between dermal and epidermal
germinative cells, thus inhibiting or altering the normal hair
cycle.
1. Grossman MC, Dierickx
C, Farinelli W, Flotte T, Anderson RR. Damage to the hair follicles
by normal-mode ruby laser pulses. J Am Acad Dermatol 1996;35:889-95
2. Proceedings of the 18th Annual
Meeting of the American Society for Laser Medicine and Surgery.
Lasers Surg Med 1998 Suppl. 10 Anstr 186-191, 198-201, 203, 205,
206.
3. Gold MH, Bell MW,
Foster TD, Street S. Long-term epilation using the EpiLight broad
band, intense pulsed light hair removal system. Dermatol Surg
1997;23:737-739
4. Goldberg DJ, Littler
CM, Wheeland RG. Topical suspension-assisted Q-switched Nd:YAG
laser hair removal. Dermatol Surg 1997 Sep;23(9):741-5
5. Lask G, Elman M,
Slatkine M, Waldman A, Rozenberg Z. Laser-assisted hair removal
by selective photothermolysis. Preliminary results. Dermatol Surg
1997 Sep;23(9):737-9
6. Proceedings of the First Intercontinental
Meeting of Hair Research Societies. Aus J Dermatol 1997;38(4):A320-A321.
7. Wheeland RG. Laser-assisted hair removal. Dermatol
Clin 1997;15:469-477
8. Hynd PI, Hughes A, Earl CR, Penno
NM. Seasonal changes in the morphology of wool follicles in Finewool
and Strongwool Merino strains grazing at different stocking rates
in Southern Australia. Aust J Agricul es 1997;48:1089-1097
9. Saitoh M, Uzuka M,
Sakamoto M. Human hair cycle. J Invest Dermatol 1970 Jan;54(1):65-81
10. Jahoda CA, Reynold AJ. Dermal-epidermal interactions.
Adult follicle-derived cell populations and hair growth. Dermatol
Clin. 1996 Oct;14(4):573-83.
11. Kim JC, Choi YC.
Regrowth of grafted human scalp hair after removal of the bulb.
Dermatol Surg 1995;21:312-313
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