Intense pulsed light

Intense pulsed light (IPL) is a technology used by cosmetic and medical practitioners to perform various skin treatments for aesthetic and therapeutic purposes, including hair removal, photorejuvenation (e.g. the treatment of skin pigmentation, sun damage, and thread veins) as well as to alleviate dermatologic diseases such as acne.^[1][2][3][4] IPL is increasingly used in ophthalmology as well, to treat evaporative dry eye disease due to meibomian gland dysfunction.^[5][6][7][8]

The technology uses a high-powered, hand-held, computer-controlled flashgun to deliver an intense, visible, broad-spectrum pulse of light, generally in the visible spectral range of 400 to 1200 nm. Various cutoff filters are commonly used to selectively filter out lower wavelengths, especially potentially damaging ultra violet light. The resulting light has a spectral range that targets specific structures and chromophores (e.g. melanin in hair, or oxyhemoglobin in blood vessels) that are heated to destruction and reabsorbed by the body. IPL shares some similarities with laser treatments, in that they both use light to heat and destroy their targets. But unlike lasers that use a single wavelength (color) of light which typically matches only one chromophore, and hence only one condition, IPL uses a broad spectrum that when used with filters, allows it to be used against several conditions. This can be achieved when the IPL technician selects the appropriate filter that matches a specific chromophore.^[9]

Description

Intense pulsed light is the use of intense pulses of non-coherent light over a range of wavelengths from 500 nm to 1200 nm.^[10] Xenon flashlamps produce high output bursts of broad spectrum. Cooling is used to protect the skin in contact with the device.

Regulations governing IPL vary by jurisdiction.^[11] "Intense Pulsed Light" is not a registered trademark. A distinction is sometimes made between beauty-grade and medical-grade machines, mainly to get around regulations. Under the CE marking system no such distinction exists.

The first FDA approval of IPL was for telangiectasias in 1995. Use quickly spread to a variety of medical and cosmetic settings. Treatment is generally safe and effective, but complications can occur such as hyperpigmentation.^[12] The polychromatic light can reach multiple chromophores in human skin: mainly hemoglobin, water, and melanin. This results in selective photothermolysis of the target, which can be blood vessels, pigmented cells, or hair follicles.

Hair removal

IPL can permanently reduce hair growth, most effectively in darker, coarser hair. There are many names and devices for pulsed light treatments such as E-Light, ELOS, and M-Light. Laser hair removal is different and uses coherent, monochromatic laser light.

Protocol

Broad-spectrum light is applied to the surface of the skin, targeting melanin. This light travels through the skin until it strikes the hair shafts or the bulb (root). The bulb is usually where the highest concentration of melanin is located. As the light is absorbed, the bulb and most of the hair shaft are heated, destroying the hair-producing papilla. It is also claimed that heat conversion occurs directly in the darker capillaries that bring blood to the follicle.

At any one time, not all hair follicles are ‘active’, and only active hair follicles can be affected by the treatment. ‘Inactive’ hair follicles can be treated as they become ‘active’ over time. For IPL treatments, an average of 8–10 treatments are required to remove most visible hair.^[13] No common treatment protocol exists and it depends on the equipment used and patient skin type. The area to be treated should be clean shaven and free of sunburn. Treatment sessions are usually 4 to 6 weeks apart. Treatments are often given in doctors' offices and so-called "medspas" by trained practitioners.

Contrary to what is often claimed, photoepilation is not a permanent hair removal method but a permanent hair reduction method. Although IPL treatments will permanently reduce the total number of body hairs, they will not result in a permanent removal of all hair.^[14] This distinction is only relevant in the USA because of FDA wording.

Certain skin conditions, health irregularities, and medications can impact whether it is safe for a person to receive a light based hair removal treatment.^[15] Photo-sensitizing medications, or damage to the skin are contraindications to treatment. According to Remington, manufacturer of an IPL device, all IPL and laser devices should only be used on light to medium skin tones, and work best on darker hair.^[16]

Efficacy

The first use of a specific IPL system developed for hair removal is reported in the literature in 1997.^[17] Hair count reduction was found to be ~60% (12 weeks), 75% (1 year), 60% (2 year). Various treatment protocols have been studied.^[18][19]

It is important to note that these studies utilized a variety of IPL devices on various skin areas, and used patients with varying hair and skin types. Thus the results are not directly comparable. In evaluating these results it is also important to remember that even a reduction of 75% indicates that 25% of the hair regrew after treatment. Permanent hair removal in these studies, as defined by the FDA, means the "long-term, stable reduction in the number of hairs regrowing after a treatment regime". The number of hairs regrowing must be stable over time greater than the duration of the complete growth cycle of hair follicles, which varies from four to twelve months by body location.^[20] No treatment to date has shown the ability to permanently eliminate all hair growth, however many patients experience satisfaction with a significant and permanent reduction.

A 2006 article in the journal "Lasers in Medical Science" compared IPL and both alexandrite and diode lasers. The review found no statistical difference in effectiveness, but a higher incidence of side effects with diode laser treatment. Hair reduction after 6 months was reported as 68.75% for alexandrite lasers, 71.71% for diode lasers, and 66.96% for IPL. Side effects were reported as 9.5% for alexandrite lasers, 28.9% for diode lasers, and 15.3% for IPL. All side effects were found to be temporary and even pigmentation changes returned to normal within 6 months.^[21]

Medical use

IPL was first developed for vascular conditions. It is at least as effective as pulsed dye lasers and can penetrate deeper with reduced risk of purpura and hyperpigmentation. IPL can also be used for the treatment of dry eye conditions such as meibomian gland dysfunction.^[22][23] IPL can treat pigmented lesions with rapid recovery. Dyschromia can be cleared after repeated sessions. Photoaging treatment has been explored. A series of IPL can be used for facial rejuvenation, improving skin laxity and collagen production. IPL combined with facial injections can be used for dynamic rhytids. Home devices have been developed recently.

IPL is employed in the treatment of a range of dermatological conditions^[24] including photodamage induced dyspigmentation and vascular changes, poikiloderma of Civatte, rosacea, acne vulgaris, sebaceous gland hyperplasia, broken capillaries/telangiectases, vascular lesions (small blood vessels), pigmented lesions (freckles, liver spots, birth marks ), melasma, actinic keratosis, photorejuvenation, basal cell carcinoma, and Bowen's disease (squamous cell carcinoma).

See also

• Electrology

References

External links

"Safety tips for intense pulsed light therapy" at fda.org