Effect of dynamic cooling on 585-nm pulsed dye laser treatment of port-wine stain birthmarks.

BACKGROUND AND OBJECTIVE: The objective of this study was to determine the effectiveness of a dynamic cooling device (DCD), spraying the skin with a brief spurt of cryogen prior to the laser pulse, in reducing transient pain associated with 585-nm pulsed dye laser (PDL) treatment of port-wine stains (PWS), and reducing epidermal damage (hypo/hyperpigmentation) caused by this laser during PWS treatment. MATERIALS AND METHODS: Matched treatment sites were compared with and without the use of the cryogen spray in 47 patients at two investigational sites. Pain ratings, clearance of the PWS, and pigmentation changes were assessed. The results were analyzed by skin type and patient age. RESULTS: A statistically significant reduction in pain ratings was found in all patient groups using the DCD without changing the efficacy of PWS clearance. Pain reduction was most remarkable in patients with darker skin types. Dynamic cooling prevented the occurrence of epidermal damage or pigmentation change in most cases. CONCLUSIONS: This study suggests that dynamic cooling can dramatically diminish pain during PWS treatment with the 585-nm PDL without reducing treatment efficacy. The absence of epidermal damage in most patients suggests that precooling with the DCD may allow the use of higher laser fluences to expedite clearance without inducing epidermal change. Dynamic cooling has potential use with other lasers and different lesions where discomfort and epidermal effects limit therapy.

A histopathological comparison of "char-free" carbon dioxide lasers.

BACKGROUND: New "char-free" carbon dioxide lasers are capable of precise tissue vaporization with minimal residual thermal damage. These lasers operate either by producing high energy, rapid pulses or by scanning a highly focused continuous mode beam. OBJECTIVE: To determine the depth of ablation and the depth of residual thermal injury produced with one to three passes of the pulsed and scanned systems. METHODS: The distal ends of preauricular donor skin from 12 patients requiring full-thickness skin grafts following Mohs micrographic surgery were treated with zero to three passes of each of the lasers, and fixed for histopathological analysis. RESULTS: The three lasers tested produced vaporization of thin (20-50 microns) layers of tissue and narrow (20-150 microns) zones of thermal injury following one, two, or three passes on intact skin. CONCLUSION: The pulsed and scanned technologies are capable of producing "char-free" tissue ablation with minimal residual thermal damage.

Treatment of small and medium congenital nevi with the Q-switched ruby laser.

BACKGROUND: The Q-switched ruby laser has been used successfully to treat a variety of benign pigmented lesions. In this study, congenital nevi (diameter, < or = 5 cm) in 18 prepubertal children were treated with the Q-switched ruby laser. OBSERVATIONS: Photographic evaluation revealed an average of 57% clearance of pigmentation in all treated nevi by the fourth treatment session and an average maximum clearance of 76% after approximately eight sessions. Greater than 90% clearance of pigment was attained in five patients. Partial repigmentation was seen in all patients who were followed up after discontinuation of therapy. Findings from histopathologic studies, obtained from one patient, revealed reduction of nevus cells in papillary dermis and upper reticular dermis that correlated with clinical lightening. There was no such reduction in the lower reticular dermis. side effects were limited to transient erythema and hypopigmentation. CONCLUSIONS: The Q-switched ruby laser effectively lightens and may clear pigmentation and eliminate superficial nevus cells from small and medium congenital nevi safely without scarring. However, these results are not permanent. The Q-switched ruby laser may be a viable alternative for providing cosmetic improvement for unresectable lesions, but it should not be considered definitive treatment. Additional studies are needed to address the long-term results of this therapy.

Skin resurfacing of fine to deep rhytides using a char-free carbon dioxide laser in 47 patients.

BACKGROUND: Recent advances in carbon dioxide (CO2) laser technology have resulted in the development of lasers that can precisely remove thin layers of skin with minimal thermal damage to the surrounding tissue. These lasers rely on rapid pulsing or scanning of the laser beam. The effects of these lasers are predictable and reproducible, making them ideal for skin resurfacing. Clinical results have been promising, however, to date, no published series exist. OBJECTIVE: To evaluate the effectiveness and side effect profile of laser resurfacing utilizing a CO2 laser with a scanning device, and make recommendations for patient selection and treatment protocol. METHODS: Patients with perioral, periorbital, and glabellar rhytides were treated with a CO2 laser with a scanning device. Utilizing chart review and photographic evaluation, patients treated between November 1994 and April 1995 were retrospectively evaluated for effectiveness of therapy, healing time, and complication rates. RESULTS: A total of 47 patients were evaluated. Photographic evaluation or chart review revealed good to excellent cosmetic results in all anatomic areas studied. All patients experienced posttreatment erythema lasting 1-6 months. Other minor complications were limited to contact dermatitis to topical preparations, transient postinflammatory hyperpigmentation, and milia formation. One patient experienced a primary herpes simplex virus infection during reepithelialization and required intravenous therapy. Minor focal atrophy was seen in one patient. No hypertrophic scarring or permanent pigmentation changes were seen. CONCLUSIONS: A CO2 laser system with a scanning beam can effectively and safely improve or remove glabellar, perioral, and periorbital rhytides.

Human dermal mast cells contain and release tumor necrosis factor alpha, which induces endothelial leukocyte adhesion molecule 1.

Tumor necrosis factor alpha (TNF-alpha) is a proinflammatory cytokine that mediates endothelial leukocyte interactions by inducing expression of adhesion molecules. In this report, we demonstrate that human dermal mast cells contain sizeable stores of immunoreactive and biologically active TNF-alpha within granules, which can be released rapidly into the extracellular space upon degranulation. Among normal human dermal cells, mast cells are the predominant cell type that expresses both TNF-alpha protein and TNF-alpha mRNA. Moreover, induction of endothelial leukocyte adhesion molecule 1 expression is a direct consequence of release of mast cell-derived TNF-alpha. These findings establish a role for human mast cells as "gatekeepers" of the dermal microvasculature and indicate that mast cell products other than vasoactive amines influence endothelium in a proinflammatory fashion.

Early cellular events in evolving cutaneous delayed hypersensitivity in humans.

The delayed-type hypersensitivity reaction (DHR) in human skin is prototypic for many inflammatory dermatoses. However the cellular events that precede gross lesion formation are unknown. In this study, inflammatory cell populations and adhesion molecule expression in early phases of DHR elicited by 2,4-dinitrochlorobenzene were evaluated. The first discernible event (at 1 hour) was mast cell degranulation, followed by induction of endothelial leukocyte adhesion molecule (ELAM-1) expression on dermal postcapillary venules at 2 hours. Endothelial leukocyte adhesion molecule expression peaked at 24 hours and declined by 48 hours. In contrast, endothelial expression of intercellular adhesion molecule-1 (ICAM-1) remained at constitutive levels. Intrafollicular T-cell migration occurred independent of ICAM-1 expression and commenced as early as 4 hours after challenge. Mature, activated CD4-positive lymphocytes that expressed a helper-inducer/memory phenotype predominated in early lesions. These results demonstrate in vivo that mast cell degranulation, ELAM-1 expression, and memory T-cell-follicular interactions are key events in subclinical evolutionary stages of cutaneous DHR.