Progressive ascending telangiectasia treated with the 585 nm flashlamp-pumped pulsed dye laser

Generalized essential telangiectasia with conjunctival involvement

Generalized essential telangiectasia (GET) is a rare skin disorder characterized by generalized development of dilated venules, which start at the lower extremities and progressively spread to the rest of the body. Mucous and conjunctival involvement is rare. The diagnosis is based on clinical examination, after excluding other primary and secondary causes of telangiectasia.

Unilateral nevoid telangiectasia – response to pulsed dye laser

BACKGROUND

Unilateral nevoid telangiectasia (UNT) is a unique vascular dermatosis of ambiguous etiology. The therapeutic role of pulsed dye laser in this condition, especially in individuals with skin types III and IV, has not been elucidated completely. The aim of this study was to assess the response to flash-lamp pulsed dye laser of UNT in Indian patients.

METHODS

A detailed analysis of nine confirmed cases of UNT patients was undertaken to determine the possible etiologic association of this disease. Six cases were treated with pulsed dye laser in combination with cryogen cooling using the following parameters: spot size, 7 mm; fluence, 5-7.5 J/cm2; wavelength, 585 nm; pulse duration, 450 micros. The procedure was repeated every 4-6 weeks and the response was assessed both clinically and photographically before each session.

RESULTS

The cases had a mean age of presentation of 20.6 years with an age of onset varying from 2.5 to 23 years. The lesions were located on the head and neck region in four patients, upper limb in four, and lower limb in one. No significant etiologic association could be established. Of the six cases treated with pulsed dye laser, a moderate response (26-50% lightening) was achieved in all cases after a mean of 2.33 sessions, a good response (51-75% lightening) was observed in four patients after 3.25 sessions, and an excellent response (>75% lightening) was found in three patients after 3.66 sessions. Mild and reversible pigmentary alterations occurred in five cases, with mild textural change in one case. There was no scarring. No recurrence was observed.

CONCLUSION

Pulsed dye laser is a useful modality for treating UNT in Indian patients. Reversible pigmentary changes are the major side-effects.

Laser-induced thermal injury to dermal blood vessels: Analysis of wavelength (585 nm vs. 595 nm), cryogen spray cooling, and wound healing effects

BACKGROUND AND OBJECTIVES

Successful laser treatment of cutaneous hyper-vascular lesions requires appropriate laser irradiation parameters for selective photothermolysis of ectatic dermal blood vessels as well as appropriate cooling parameters for epidermal protection based on an individual patient basis. Using the rabbit ear as an in vivo model for dermal vasculature, we investigated the influences of laser wavelength (585 nm vs. 595 nm) and cryogen spray cooling with various spurt durations on the laser-induced thermal injury to dermal blood vessels. Wound healing response was also evaluated in 2 hours and 4 days.

STUDY DESIGN/MATERIALS AND METHODS

Flashlamp-pumped pulsed dye laser ScleroPlus (operated at the wavelength of 585 or 595 nm) was used for the comparison between the influences of two wavelengths (585 nm vs. 595 nm). R134-a cryogen spurts with the durations from 50 to 300 milliseconds were sprayed onto the sites to be irradiated and terminated 20 milliseconds before the onset of the laser pulses. In vivo rabbit ear was used as the model for cutaneous hyper-vascular lesions. Totally 10 New Zealand Albino white rabbits were experimented and in each rabbit ear six to seven sites were irradiated. Five animals were sacrificed 2 hours after the irradiation, and the remaining five sacrificed 4 days after the irradiation. Thermal injury to the blood vessel was assessed by hematoxylin and eosin stained histological sections and confirmed by an apoptosis assay.

RESULTS

When the radiant exposures were above 10 J/cm2, 595 nm wavelength induced equivalent or more severe thermal injury to dermal blood vessels than 585 nm. Cryogen spray cooling with the spurt durations above 100 milliseconds resulted in increased depth of the most superficial thermal injury to dermal blood vessels than without cooling, indicating that superficial blood vessels were non-specifically cooled by the cryogen spurts applied at these parameters. Laser-induced thermal injury was significantly healed in the rabbit ear vasculature at 4 days post irradiation.

CONCLUSIONS

Given sufficient radiant exposure, 595 nm wavelength can induce equivalent or more severe vascular injury compared with 585 nm. Cryogen spray cooling with the spurt durations above 100 ms may impair the photocoagulation of superficial blood vessels. Irreversible thermal injury to blood vessel can be achieved only when the basement membrane of blood vessel wall is irreversibly damaged.

Intense pulsed light therapy in the management of hereditary benign telangiectasia

Hereditary benign telangiectasia is an idiopathic condition that causes considerable cosmetic embarrassment but has eluded successful treatment due to its extensive nature. We report a case of hereditary benign telangiectasia of the lower limbs in which the challenge of treating an extensive vascular lesion is met by using an Intense pulsed light (IPL) source.

Thermal response of human skin epidermis to 595-nm laser irradiation at high incident dosages and long pulse durations in conjunction with cryogen spray cooling: an ex-vivo study

BACKGROUND AND OBJECTIVES

Improved laser treatment of cutaneous hypervascular lesions is expected by utilizing higher incident dosages, longer pulse durations and longer wavelengths than those currently used in clinical settings. However, simply increasing the incident dosage will also increase the risk of nonspecific thermal injury to the epidermis due to light absorption by melanin. In this study, we investigated the thermal response of human skin epidermis to 595-nm wavelength laser irradiation at high incident dosages (up to 20 J/cm(2)) and long pulse durations (up to 40 milliseconds) in conjunction with cryogen spray cooling (CSC) using ex-vivo human skin samples.

STUDY DESIGN/MATERIALS AND METHODS

The Candela V-beam trade mark laser (595-nm wavelength) was used in the experiments. Ex-vivo human skin samples (Fitzpatrick types I-VI) were irradiated at the incident dosages D(0) = 4, 6, 10, 15, and 20 J/cm(2), laser pulse durations tau(laser) = 1.5, 10, and 40 milliseconds, without and with CSC (refrigerant-134A, spurt duration tau(CSC) = 100 milliseconds). Thermal injury to the epidermis was evaluated by histological observations.

RESULTS

Under the same incident dosage, longer pulse durations led to reduced thermal injury to the epidermis. Without CSC, no demonstrable thermal injury to the epidermis was observed in skin types I-II irradiated at the incident dosage as high as 15 J/cm(2), and in skin types III-IV at 10 J/cm(2). When CSC was applied, no evidence of thermal injury to the epidermis was present in skin types I-II even when irradiated at the maximum available incident dosage of the laser system (20 J/cm(2)). In skin types III-IV, no demonstrable thermal injury to the epidermis was observed when using incident dosage as high as 15 J/cm(2) in conjunction with CSC. In skin type VI, thermal injury to the epidermis could not be avoided even at the setting D(0) = 4 J/cm(2), tau(laser) = 40 milliseconds in conjunction with CSC.

CONCLUSIONS

For a given incident dosage, longer pulse durations help reduce thermal injury to the epidermis. When a 100-millisecond cryogen spurt is applied, thermal injury to the epidermis can be prevented in ex-vivo skin types I-IV when irradiated at higher incident dosages (15-20 J/cm(2)) than those currently used in clinical settings. Further studies on optimizing the CSC parameters in conjunction with the laser irradiation parameters are needed to protect skin types V-VI from thermal injury to the epidermis.