Intense pulsed light (IPL) devices were first introduced into medical practice in 1997 and have since attained a wide cosmetic application in dermatology (Raulin et al, 1997). Since its introduction, IPL has been used to treat vascular lesions, pigmented lesions and excess or unwanted hair. IPL can be defined as a non-laser incoherent light emitted from a high output flashlamp at a concentrated point, which triggers energy absorption in the affected areas (Goldberg, 2012). It has reached a level of safety and effectiveness that has seen its adoption by a broad range of commercial cosmetic platforms across the globe. Today, it is a popular and reasonably affordable treatment that is often offered in lieu of laser treatments for its affordability and, in the case of newer IPL technologies, its equal or increased effectiveness in the treatment of certain cosmetic dermatological conditions.
IPL is a common treatment option for telangiectasia (thread veins). Thread veins, also referred to as spider veins, are the smaller or smallest veins of the complex venal network, which ultimately drains into the heart. They represent the veins closest to the surface of the skin that often manifest as vascular lesions. Such lesions are common around the cheeks, nose, and mouth, and it is usually when the veins appear in these locations that cosmetic treatment is sought. The deep blue colour of the most conspicuous thread veins (those closest to the surface of the skin) is particularly difficult to conceal on a daily basis with cosmetic products. It is for this reason also that patients often present with this condition.
There is currently no medical scientific consensus on what underlying factors contribute to the prominence of these veins in certain individuals beyond the fact that there are likely several, in proportions that differ from case to case. Their proximity to the surface is what makes thread veins both visible and treatable, with no impact on the larger vascular network. Larger veins are typically subdermal, meaning that they are invisible, and therefore present no cosmetic issue to be rectified.
Conventional laser treatment remains the most common treatment for vascular lesions as a whole (Railan et al, 2006) and is still employed almost exclusively for more significant cosmetic issues, such as port wine birthmarks, haemangiomas and a continually expanding range of dermatological cosmetic conditions. However, IPL has gained ground over lasers for the treatment of less conspicuous cosmetic issues, and it has several advantages over laser treatment, most significantly where postoperative issues are concerned.
Generally, IPL treatment is less invasive than laser and leads to less recovery downtime. It is not an appropriate treatment for all vascular lesions and generally has a narrower application than laser treatment; however, where it can be implemented, the advantages make it a preferable choice to laser treatment. This is almost certainly one of the reasons for its wide availability from a number of cosmetic medical practices.
Mechanism
As with all cosmetic treatments that are practically applied, the function of IPL is based upon a technical principle and realised through technical application.
The light produced by IPL devices is defined as non-laser, high-intensity noncoherent light. It is produced via a high output flashlamp and normally falls within the range of 500–1200 nm. The noncoherent nature of the light is achieved via bursts of electrical current passing through a gas chamber typically filled with xenon (favoured for its luminosity when charged). This light is directed to the end of a handpiece and applied to the skin after passing through a conduction composed of either sapphire or quartz. The diameter of handpiece's distal end allows for a precise application of these light pulses directly onto the lesions to be treated. During application, contact of the epidermis with the conduction crystal necessitates a specific cooling system (Weiss and Sadick, 2000), and several can be used. Different systems may opt for a cryogen spray, contact cooling or forced refrigerated air.
The IPL flashlamp device has a broad wavelength output, which allows for precision and control of the energy absorbed by the skin and will be explored further in the next section. The light emitted by an IPL device contains green, yellow, red and infrared wavelengths simultaneously discharged. The duration of each pulse, the relative intensity and the spectral distribution can all be controlled. In particular, pulse duration can vary widely between different IPL systems. While some systems make use of single pulses, most use two pulses (or, more accurately, sub-pulses) to induce intrapulse epidermal relaxation. Controlled by algorithm, the precise duration of these pulses varies according to needs (this will be explored further in the next section).
In combination with the narrow dimensions of the equipment, this allows for a precise control and confinement of the energy delivery into the tissue, ensuring no damage (or any effect at all) to the surrounding areas and the precise energy delivery necessary for treating the issue in question.
The most important parameters that control the operation of an IPL system are as follows:
- Energy density (or fluence): most basically defined as the optical energy delivered per unit area. Variance in this parameter can increase over the lifetime of an IPL system
- Pulse duration: this is critical to the efficacy of any IPL system. Newer IPL systems make use of sub-pulses
- Spot size: this will naturally affect the precise of any IPL system. The delivery of consistent energy over this area is one of the advantages of squared pulse IPL systems
- Average spectral output: this is defined as the average wavelength across the various pulses and sub-pulses of in IPL system. Double filter IPL systems have the advantage of removing undesirable wavelengths and bringing this parameter into a more acceptable range.
All of these can be altered in several ways; some may vary with the IPL system used and some may depend on the equipment itself.
Effect and principle
The efficacy of IPL treatment relies on the principle that certain targets for energy absorption can absorb the energy from the broad spectrum of light produced by the IPL equipment without exclusively doing so via their highest absorption peak. These targets are known as chromophores. A chromophore is the region within the tissue molecule where the energy difference between two separate molecular orbitals falls within the range of the visible spectrum (Pharmatutor, 2019). Thus, by targeting these chromophores with the visible light of the IPL device, the energy is absorbed. This selective absorption is the principle allowing for precision in the application of IPL to the effected tissue areas.
The principle is known as selective photothermolysis and allows for light radiation damage to be confined to specifically selected dermal and/or epidermal targets, so defined by chromophores identified at the cellular or tissue structural level (Anderson and Parrish, 1983). There is a high degree of precision involved in this process, to such a degree that even cells adjacent to those targeted can be spared any radiation damage.
With IPL systems that make use of two or more sub-pulses within every perceived pulse, pulse duration can be extended without the risk of heat diffusion into the surrounding tissue. Controlled by algorithm, these two pulses allow for interpulse thermal relaxation and vary according to the thermal relaxation time (TRT) of the chromophores to which IPL is applied. TRT is how long it takes for an object to lose heat energy. So, in the context of IPL, it is the time taken for the tissue to lose the heat energy that was just applied by the IPL. Typically, it is measured as the time taken for that maximum temperature to drop below 50%.
The three prominent chromophores of human skin are haemoglobin, water and melanin, which all have wide absorption peaks. This means that monochromacy of the light beam is not essential, because these chromophores will be targeted simultaneously by a range of wavelengths. This leads to a general efficiency of the IPL treatment, in tandem with its precision.
By limiting the wavelengths emitted by the IPL pulses, precision can be increased by limiting in turn the desired targets. This is achieved by the use of dichroic ‘cut-off’ filters and allows the light to target, more exactly, certain cellular or dermal structural elements. Most IPL devices have two cut off filters, but many more can be installed and are frequently in use where greater precision is called for.
» IPL does not produce purpura because the aim in its use to treat thread veins and other lesions is to raise the temperature of the vessels high enough to trigger coagulation, which in turn leads to their destruction. These veins are then naturally replaced by fibrous granulation tissue, causing no purpura or lengthy post-procedural downtime «
General advantages
Despite the high degree of precision afforded by IPL treatment, the spot size of each pulse is actually relatively large compared to laser treatments. However, contrary to what might be expected, this is in fact an advantage in the majority of cases. A large spot size—or footprint, as it is occasionally known—allows the total number of pulses required for a single session to be kept to a minimum and allows for swift treatment of large areas of tissue. In cases such as port wine birthmarks or other large lesions on the skin, this is an advantage, and also contributes to a less strenuous and lengthy postoperative recovery period. On account of this large spot size, there is a certain manoeuvrability issue, especially when treating uneven skin surfaces. Nevertheless, potential improvements, such as handpiece size, offer prospects for future amelioration of such issues.
The wavelengths of light emitted by an IPL device can be customised to increase precision in the cellular structures that are specifically targeted. Beyond wavelength, there are several other parameters that can be customised, increasing the general versatility of the device. Such parameters, including pulse duration, pulse delay time and pulse sequences, are fully customisable.
The latest IPL systems also make use of double light filters, which represents a development in the earliest single filter technology. This improvement allows for the removal of those wavelengths of light most likely to harm surrounding tissue before they come within an effective proximity.
An important principle of IPL is that the amount of light emitted is proportional to the pattern of current through the flashlamp. Earlier IPL systems would operate with a Gaussian current pattern, which would produce an uneven beam distribution over the pulse, leading to central hot spots. New squared pulse IPL devices overcome this obstacle by producing a square-shaped beam with a stable, flat and homogenous spectral output across its area. This improves precision by eliminating variance in the pulse intensity across the area of the pulse.
Such versatility and the significantly lower costs of IPL compared to most single-spectrum lasers are the major factors that have contributed to the proliferation of IPL technology since its initial development. This has led to its use in several clinical applications. Not least, the generally lower intensity of IPL has seen it become, in a number of cases, the preferred treatment over laser for dermatological issues. Early claims of excessive side effects and limited efficacy have largely been answered by developments in the technology since its inception in the 1990s. It is now considered to be a fully reliable treatment option.
Thread veins
The treatment of thread veins, most often on the face or other typically visible areas of the body (Figure 1), has become one of the most common applications of IPL treatment in cosmetic medicine. Most cases involving vascular lesions can be treated with IPL, but the treatment is particularly popular for the treatment of thread veins and other smaller and less conspicuous dermatological conditions.
Figure 1. The treatment of thread veins, most often on the face or other typically visible areas of the body, has become one of the most common applications of intense pulsed light treatment in cosmetic medicine
In the absence of any solid knowledge regarding the precise cause of vascular lesions, there are currently no medicinal and dietary treatments available. For this reason, the alternative to IPL is, most frequently, single-wavelength laser treatment. From the perspective of patients, this is rarely an attractive choice for thread vein treatment, as it is a relatively minor cosmetic condition that may not appear to warrant the intrusive nature and discomfort of laser treatment or the significant postoperative recovery period. However, conventional laser treatment generally remains the most popular option for the treatment of vascular lesions.
Regarding this recovery period, the primary reason that IPL treatments are generally less onerous lies in the absence of postoperative purpura, which is a typical side effect of laser treatment of vascular lesions and very often a necessary one if a desired reduction in vein visibility is to be achieved. With IPL treatments, excessive purpura is not a side effect, and, as a result, the post-procedural downtime is greatly minimised.
IPL does not produce purpura because the aim in its use to treat thread veins and other lesions is to raise the temperature of the vessels high enough to trigger coagulation, which, in turn, leads to their destruction. These veins are then naturally replaced by fibrous granulation tissue, causing no purpura or lengthy post-procedural downtime (Anderson and Parrish, 1983).
Diagnosis and treatment of thread veins
Those who present to cosmetic medical practitioners for the treatment of visible veins typically do so because these veins are judged to be excessively conspicuous. These can often be large, subdermal veins and, in such cases, invasive surgery is nearly always required. On the other hand, IPL treatment is reserved for smaller capillary veins that are closer to the surface of the skin. This is what is typically understood as thread veins and should be accurately diagnosed before treatment is recommended.
In many cases, screening questions are sufficient to diagnose thread veins. Additionally, in most cases, if a photograph is supplied by the patient, physical consultation is unnecessary (Smith and Whiteley, 2019). Screening questions should determine the size and general appearance of the veins, as well as the precise location upon the body, as there is a strong correlation between anatomical location and the types of veins that are likely to be visible.
Diagnosis is a necessary precursor to IPL treatment, as it is not appropriate in cases involving deeper and larger veins. Accordingly, diagnostic information should be checked against a series of basic classifications/criteria that identify thread veins. To diagnose thread veins, specific criteria must be met.
Appearance
Typically, thread veins are very fine veins that provide a superficial function in blood circulation. Therefore, their destruction does not come with any serious consequences. The actual thread veins are colourless but derive their colour (blue or red) from the blood within.
Anatomical location
In most cases, patients with thread veins present with them on the cheeks, chin and/or nose. Veins around the eye sockets and forehead are typically deeper subdermal veins, and, therefore, less appropriate for IPL treatment. However, thread veins can also be found in these areas.
Thread veins often occur in dense groupings in specific areas of the face. If they are sufficiently dense and arterial in nature, they may give the impression of red patches or a general blotchiness. At the point of diagnosis, it is important to distinguish such cases from diffuse redness or rosacea (commonly known as flushed skin or a having a ‘high colour’), as this is a different condition. It is in such cases that a patient-supplied photograph—if the diagnosis is not conducted face-to-face—is essential.
Another important diagnostic distinction involves clusters of thread veins on or around the nose. Thread veins may occur on the nasal alar, the nostrils and the bulb of the nose. In the latter case, sufficiently dense clusters of thread veins can give the appearance of general rosacea in this area. Due to common associations of such symptoms with alcoholism, patients may present to medical cosmetic practitioners with this issue as a result of this misconception. In such cases, it is vital to determine that rosacea and swelling due to alcohol is not the cause before treatment with IPL can begin. Rhinophyma is another condition that may cause these symptoms. Again, this must be ruled out before a diagnosis of thread veins is made and IPL is recommended.
Thread veins can appear in many areas of the body. However, as patients most often present on account of cosmetic concerns, most thread veins cases that are likely to be treated occur on visible parts of the body. Of these visible thread veins, facial cases make up the overwhelming majority. Due to this, an important principle to apply when making a diagnosis is that these thread veins are located above the heart. Accordingly, valve failure and veinous reflux can normally be ruled out. Therefore, procedures that are normally used to identify valve failure, such as ultrasonography, are unnecessary.
Recommending treatment
The proliferation of IPL treatment for thread veins has largely come at the expense of transdermal single-wavelength laser treatment. Nonetheless, there are several other treatment options for thread veins and other vascular lesions that, in certain cases, are more appropriate and may be recommended instead of IPL.
Electrocautery
Generally, IPL is the optimal treatment for superficial thread veins. However, in cases where these veins are not considerably numerous and the general redness is not particularly severe, electrocautery may be a preferable treatment (Mujadzic et al, 2015).
Electrocautery generates heat near the point of a needle by a rapidly alternative current and, thus, polarity. By attracting and repelling electrons in the target tissue at a very high frequency (ranging from kilohertz to megahertz), heat is generated within the tissue, which destroys the vein or artery. Unlike IPL, electrocautery bypasses any stage of coagulation and resultant tissue replacement and, therefore, is only appropriate for the smallest and most superficial thread veins.
Within the medical community, in the past, there has been a near consensus that electrocautery is inappropriate for all such cosmetic applications except hair removal. Nevertheless, with technical experience and by limiting its use to only the most superficial and least densely packed thread veins, the technique can be highly effective.
A further advantage of electrocautery is that the equipment is relatively cheap; however, its limited applicability means that it can rarely be relied upon as a treatment option for the majority of the vascular lesion cases.
Sclerotherapy
Sclerotherapy as a treatment option for vascular lesions is controversial due to the slight risk of severe side effects (Watson and Mansour, 2017). With technical experience and adherence to stringent guidelines (which are now standard) (Khunger and Sacchidanand, 2011), sclerotherapy can, in some cases, be an effective and safe means of treating several types of vascular lesions, including thread veins (Figure 2).
Figure 2. Sclerotherapy can be an effective and safe means of treating several types of vascular lesions, including thread veins
Sclerotherapy involves the injection of sclerosant (most commonly sodium tetradecyl sulphate) directly into the vein. This causes the vein to scar and build with fibrous tissue (Mayo Clinic, 2021). In turn, this causes blood to reroute into other veins (normally deeper ones), thus removing the visible vein by draining it of the blood that gives it its colour.
The risks of sclerotherapy nearly all involve the inadvertent injection of the sclerosant into arterioles, which can lead to skin necrosis or even blindness in one eye (Arunakirinathan et al, 2019). For this reason, sclerotherapy should only be applied in the cases of larger thread veins, and precision is of the utmost importance.
When applied professionally, the risks are low; however, patient reluctance is likely considering their severity. For this reason, as well as its limited applicability where facial thread veins are concerned, sclerotherapy does not represent a major challenge to the proliferation of IPL and is relatively rarely an acceptable alternative.
Transdermal laser
As mentioned, laser treatment is still the most common alternative to IPL for the treatment of thread veins and the most common treatment for vascular lesions in general. In the majority of cases where IPL is rejected, laser treatment will be chosen as an alternative.
The advantages of laser treatment over IPL arise in cases where the thread vein lies deeper in the skin and is larger. Both IPL and laser treatments work by targeting the specific chromophores that correspond to either arterial (oxyhaemoglobin) or ventricular (deoxygenated haemoglobin) thread veins. However, in the case of laser, the higher energy levels and narrower wavelengths emitted can pass through the epidermis to deeper veins, which cannot be reached by IPL.
The disadvantages here include the tissue damage involved in those same higher intensity levels, causing purpura and significant postoperative downtime. As this occurs, even when laser is used to treat more superficial thread veins, IPL is clearly preferable in these cases. IPL and laser treatments are compared in Table 1.
Table 1. Transdermal laser versus intense pulsed light (IPL)
| Transdermal laser | IPL |
|---|---|
| Preferable for deeper/larger lesions | Preferable for superficial lesions (thread veins) |
| Significant postoperative downtime | Little to no postoperative downtime |
| Can cause purpura | No purpura |
| Smaller spot size (and thus better manoeuvrability) | Larger spot size (manoeuvrability issues on uneven skin surfaces) |
Conclusion
Since its introduction in the 1990s, IPL has proliferated among cosmetic medical practitioners and is now a popular choice for the treatment of thread veins. Its success has been aided by the several conditions that it has been shown to treat more effectively than alternative options. While laser treatment, which represents the method's primary competitor, is preferable for deeper vascular lesions, several advantages make IPL preferable in the treatment of thread veins. Leading among these is IPL's less intrusive nature and the absence of post-operative downtime for patients. For proper application of IPL treatment, stringent diagnostic criteria must be adhered to and the procedures must be compared to alternative options. In such cases, IPL very often proves to be the best choice, with only laser treatment being employed in as many cases.
Key points
- Intense pulsed light is an alternative to laser treatments due to its lower cost and equal effectiveness in many cases
- Thread veins are most often found on the face or other typically visible areas of the body
- Screening questions are usually sufficient to diagnose thread veins, and, if a photograph is supplied by the patient, physical consultation may be unnecessary
- Electrocautery, sclerotherapy and transdermal laser treatment are all alternatives to treat thread veins in certain cases.
CPD reflective questions
- What is considered to be the most effective treatment for thread veins?
- Taking onboard the difference between intense pulsed light and lasers, what would be the rational for choice?
- Would this be a treatment you would consider introducing to your medical clinic and why?