Laser treatment of cutaneous malignancies.

The unique characteristics of lasers and their effects upon tissue form the basis for the medical use of lasers. As laser technology makes rapid strides and advances, it is important for dermatology nurses to understand the usefulness of the currently available lasers and the limitations and potentials of this mode of therapy for cutaneous malignancies.

Common skin disorders of aging: diagnosis and treatment.

The incidence of skin disorders increases with age because of changes in skin structures and a lifetime accumulation of environmental insults. Photoaging, resulting from exposure to harmful ultraviolet wavelengths in sunlight, is responsible for many common skin disorders, from wrinkles to melanoma. Older patients also see their physicians with complaints of various types of dermatitis, including contact and seborrheic. Although skin disorders vary in severity, they all adversely affect an older patient's health and/or quality of life. Early recognition, prevention, and treatment of skin diseases by the primary care physician is therefore an important element in the overall care of the middle-aged and older patient.

Alteration of argon laser-induced scars by the pulsed dye laser.

Ten patients with portwine stains (PWS) with test sites previously exposed to an argon laser were evaluated and subsequently treated with five pulsed dye (585 nm) laser treatments over a 10 month period. Clinical assessments, skin surface texture analyses using optical profilometry, and light microscopic histological evaluations were performed prior to commencement and at the end of the study in all ten patients. A change in the skin texture with return of skin markings approximating those of normal skin measured by optical profilometry was observed in the argon treated PWS skin following pulsed dye laser treatments.

Primary localized cutaneous amyloidosis.

Fifty-seven patients with primary localized cutaneous amyloidosis (PLCA) were clinically and histopathologically reviewed. Two-thirds of patients had macular amyloidosis (MA). Intermediate cases having macular lesions with micropapules and/or lichens were identified. A spectrum for the disease is proposed, in which the less itchy classical macular variant occurs at one end and the very pruritic traditional lichen variant at the other. The salient histopathologic findings were similar in the macules, micropapules, and lichens, but were more prominent in the lichens. These consisted of hyperkeratosis, keratinocyte degeneration, satellite cell necrosis, and basal cell destruction. Amyloid deposition in the dermal papillae with transepidermal elimination, dermal melanophages, and superficial perivascular inflammation were also present. These changes represent an interface dermatitis of the vacuolar type. PLCA may be categorized under the group of dermatoses characterized by a lichenoid tissue reaction; inflammation may play a key role in mediating these disorders.

Pulse duration effects on cutaneous pigment.

Melanin, an endogenous chromophore in pigment containing cells in skin, is being specifically altered by lasers using the principle of selective photothermolysis (SPT). This implies that a combination of specific laser parameters of wavelength, pulse duration, spotsize, and energy density are required to confine the delivered laser energy to the targeted cells alone. Because the bulk of cutaneous pigment is localized to epidermal basal cells, pigmentary incontinence has been found to occur in skin exposed to laser irradiation. This study demonstrates that pulse duration or exposure time of the laser affect the severity of pigmentary incontinence induced. Pigment granules are more abundant, aggregated, and located deeper in the dermis following exposure to 500 nsec pulse duration than 100 nsec at a wavelength of 504 nm. This relationship appears to be independent of the laser energy density used.

Pulsed dye laser treatment of benign cutaneous pigmented lesions.

Superficial benign cutaneous pigmented lesions that commonly present to the dermatologists and plastic surgeons have been treated by many conventional modalities such as dermabrasion, depigmenting creams as well as several types of lasers. Many of these treatment modalities lack specificity of injury, which has meant that normally pigmented and even non-pigment containing structures such as collagen as well as the hyperpigmented lesion itself have all been indiscriminately destroyed. This has resulted variously in hypopigmentation, hyperpigmentation, in addition to scar formation in some cases. A coaxial 504 nm laser with a pulse duration of 300 nsec was used to treat fifty two patients with superficial benign cutaneous pigmented lesions. Although the number of treatments required to clear the lesion varied according to the type of lesions being treated, on average, between 2 and 4 treatments were required to completely eradicate the superficial benign cutaneous pigmented lesions using 504 nm pulsed dye laser. The skin at the site successfully cleared of the pigmented lesion remained normal in skin color, texture, markings, and mobility.

585 nm for the treatment of port-wine stains.

Although the flashlamp-pulsed-dye laser has been successfully used for the treatment of port-wine stains (PWS) at 577 nm, a number of adult patients had incomplete clearance of their birthmarks with this treatment modality because of residual vessels lying beyond the 0.75-mm penetration depth of 577-nm irradiation. Fifteen adult patients, of whom nine were previously treated with limited success at 577 nm (group A), and six untreated patients (group B) were included in the study. For the group A patients, treatment with 585 nm produced successful clearance of the birthmark. For the six patients in group B, parallel treatment of different sites of the same lesion coupled with skin biopsies and histologic examination revealed that a change in the wavelength from 577 to 585 nm allowed the laser light to penetrate from the midreticular dermis into the subcutaneous fat. This explained the clearance achieved at 585 nm and not at 577 nm.

Histologic comparison of the pulsed dye laser and copper vapor laser effects on pig skin.

Albino pig skin was exposed to the copper vapor (CVL) and flash-lamp pulsed dye (PDL) lasers at 578 nm with a 3 mm diameter spotsize over a range of fluences until purpura and whitening were first established. The total irradiation time was the parameter that was varied in order for the CVL to reach the desired fluence. The lowest fluence producing each clinical endpoint was designated the threshold fluence: 34 J/cm2 was required to produce purpura using the CVL compared to 7.5 J/cm2 with the PDL laser. Histologically, skin exposed to purpura fluences from the CVL revealed the presence of constricted, disrupted papillary dermal blood vessels with trapped RBC's within them which were unlike those exposed to PDL where the irradiated vessels were dilated and packed with masses of intravascular agglutinated RBC's. The whitening threshold fluences for the CVL and PDL lasers were 67 J/cm2 and 29 J/cm2, respectively. Streaming of epidermal cells and dermal collagen denaturation were observed in CVL irradiated skin, compared to occasional dyskeratotic epidermal cells and focal dermal collagen denaturation following PDL exposure. The mechanisms responsible for the clinical and histologic changes produced by the two laser systems are discussed.

Action spectrum of vascular specific injury using pulsed irradiation.

It has been clearly demonstrated that cutaneous blood vessels will be selectively damaged by a laser whose wavelength matches one of the three absorption spectral peaks of the chromophore, oxyhemoglobin, for example, 577 nm. A restriction in the application of this wavelength for the treatment of benign cutaneous vascular tumors, such as portwine stains, has been the penetration depth of 577 nm irradiation of approximately 0.5 mm from the dermal epidermal junction (DEJ). This study was undertaken to establish whether it was possible to increase the penetration depth from 0.5 mm by changing the wavelength to beyond 577 nm in albino pig skin. Results from this study confirm that penetration depth increases from 0.5 to 1.2 mm by changing the wavelength from 577 to 585 nm at 4 J/cm2, while maintaining the same degree of vascular selectivity as that previously described after 577 nm irradiation. This occurred in spite of a mismatch in the wavelength between 585 nm and the oxyhemoglobin absorption peak of 577 nm. Unlike 585 nm irradiation and in contrast with theoretical predictions, 590 nm laser light did not penetrate as deeply as 585 nm. Not only was there a reduction in the penetration depth of the laser beam from 1.2 mm at 585 nm to 0.8 mm at 590 nm, at 4 J/cm2, but there was also a decrease in vascular selectivity in albino pig skin exposed to 590 nm irradiation.

Effect of wavelength on cutaneous pigment using pulsed irradiation.

Several reports have been published over the last two decades describing the successful removal of benign cutaneous pigmented lesions such as lentigines, café au lait macules' nevi, nevus of Ota, and lentigo maligna by a variety of lasers such as the excimer (351 nm), argon (488,514 nm), ruby (694 nm), Nd:YAG (1060 nm), and CO2 (10,600 nm). Laser treatment has been applied to lesions with a range of pigment depths from superficial lentigines in the epidermis to the nevus of Ota in the reticular dermis. Widely divergent laser parameters of wavelength, pulse duration, energy density, and spotsizes have been used, but the laser parameters used to treat this range of lesions have been arbitrary, with little effort focused on defining optimal laser parameters for removal of each type. In this study, miniature black pig skin was exposed to five wavelengths (504, 590, 694, 720, and 750 nm) covering the absorption spectrum of melanin. At each wavelength, a range of energy densities was examined. Skin biopsies taken from laser-exposed sites were examined histologically in an attempt to establish whether optimal laser parameters exist for destroying pigment cells in skin. Of the five wavelengths examined, 504 nm produced the most pigment specific injury; this specificity being maintained even at the highest energy density of 7.0 J/cm2. Thus, for the destruction of melanin-containing cells in the epidermal compartment, 504 nm wavelength appears optimal.

Behçet's disease. New perspectives on an enigmatic syndrome.

Behçet's disease is a multifaceted syndrome characterized by oral and genital ulcerations and ocular abnormalities including keratitis, optic neuritis, and uveitis. The disease has multiple systemic associations that include involvement of the gastrointestinal, cardiovascular, and central nervous systems as well as the joints, blood vessels, and lungs. Infrequently observed in the Americas and Western Europe, it has been more commonly seen in Turkey and Japan. Human lymphocyte antigen (HLA)-Bw51, HLA-B27, and HLA-B12 have each been associated with various manifestations of Behçet's disease. Numerous etiologies have been proposed, including environmental, virologic, bacterial, and immunologic factors; an autoimmune basis, characterized by circulating immune complexes and complement activation, has gained increasing acceptance. Although tetracycline remains the drug of choice for the oral ulcers of Behçet's disease, topical corticosteroids and topical anesthetics have been used for both oral and genital involvement. Oral corticosteroids continue to be the mainstay of systemic therapy, although various immunomodulators and anti-inflammatory agents, such as azathioprine, cyclophosphamide, chlorambucil, colchicine, dapsone, and cyclosporine, have been employed successfully.

Spotsize effects on guinea pig skin following pulsed irradiation.

Laser irradiation parameters such as wavelength, irradiance (W/cm2), and pulse duration have been clearly shown to influence the extent to which tissue is damaged. The careful choice of these parameters can result in confining laser injury to specific targets in tissue. Spotsize, a parameter not commonly appreciated in the application of lasers to medicine and surgery, has been shown, in this study, to contribute to the ultimate outcome of laser effects in tissue. A series of histological events occurring in the skin are demonstrated to be directly related to the effects of spotsize on tissue at a fixed exposure time and wavelength. Many of these changes could contribute to unwanted adverse effects, such as scarring, which occur following certain laser therapies.

Sporotrichoid leishmaniasis in patients from Saudi Arabia: clinical and histologic features.

The clinical and pathologic presentations of cutaneous leishmaniasis in the various countries of the Middle East are well documented. The defined patterns currently encountered in the region emphasize the rarity of local extension of the infection from the bite site. Between 1970 and 1980 we have seen 24 patients with cutaneous leishmaniasis who acquired the infection in Saudi Arabia. In these patients there were several interesting variations from the hitherto described patterns of Oriental sore. The variations include, clinically, the appearance of satellite lesions and the presence of sporotrichoid spread of infection; and histologically, the presence of stellate intradermal abscesses. Such variations in the clinical and pathologic presentations may be due to differences either in the host's immunologic reactivity or in the Leishmania organisms found in Saudi Arabia. Speculative evidence supports the possibility of a different strain and/or species of Leishmania tropica in Saudi Arabia, which in turn may be responsible for this unique clinicopathologic presentation.