Laser treatment of tattoos in darkly pigmented patients: efficacy and side effects.

BACKGROUND: Many modalities for the treatment of tattoos and pigmented lesions produce a greater risk of complications in Fitzpatrick types V and VI skin because of an increased incidence of adverse pigmentary changes and keloidal scarring. In fair-skinned persons Q-switched lasers have proved effective in removing pigmented lesions and tattoos without scarring. OBJECTIVE: This study was conducted to determine the efficacy and effects of Q-switched lasers on a small series of darkly pigmented patients with tattoos. METHODS: Four patients of Ethiopian origin with facial and neck tribal tattoos were treated with both the Q-switched ruby and Nd:YAG lasers. One black woman with a multicolored tattoo on the mid chest was treated with the Q-switched ruby laser. RESULTS: Clearing of all lesions was seen. The treatments did not result in scarring or permanent pigment changes other than the ones intended. CONCLUSION: Our results indicate that in darkly pigmented patients, Q-switched laser treatment of tattoos can be performed successfully. The longer wavelength Q-switched Nd:YAG laser is recommended when removing tattoos in darker complected persons. A test treatment is advised before treatment of large skin areas.

Diagnosis and treatment of nevomelanocytic lesions of the skin. A community-based study.

BACKGROUND AND DESIGN: Nevomelanocytic lesions of the skin are frequently removed. However, little data are available concerning the diagnostic accuracy, histologic features, and methods of removal for these common lesions. We identified 2935 consecutive nevomelanocytic lesions examined at four pathology laboratories to determine the accuracy of the preoperative diagnosis, the characteristics of the patients treated, and the methods used for removal. RESULTS: Of 2935 melanocytic lesions, 2087 (71%) were benign nevi, 684 (22%) were dysplastic nevi, 72 (3%) were blue nevi, and 76 (3%) were lentigines. Lentiginous melanocytic hyperplasias with cytologic atypia (20) and melanoma (26) each represented less than 1% of such lesions. Diagnostic accuracy varied by the pathologic diagnosis and the specialty of the treating physician. Dermatologists and plastic surgeons had the highest diagnostic accuracy. Techniques used to remove melanocytic lesions varied by physician specialty and type of lesion. CONCLUSIONS: Despite the high frequency of removal, the methods used to remove nevomelanocytic lesions vary widely. Improving the clinician's ability to distinguish type of lesion may improve care. Studies that determine optimal means for their removal are warranted.

Dye-enhanced laser welding for skin closure.

The use of a laser to weld tissue in combination with a topical photosensitizing dye permits selective delivery of energy to the target tissue. A combination of indocyanine green (IG), absorption peak 780 nm, and the near-infrared (IR) alexandrite laser was studied with albino guinea pig skin. IG was shown to bind to the outer 25 microns of guinea pig dermis and appeared to be bound to collagen. The optical transmittance of full-thickness guinea pig skin in the near IR was 40% indicating that the alexandrite laser should provide adequate tissue penetration. Laser "welding" of skin in vivo was achieved at various concentrations of IG from 0.03 to 3 mg/cc using the alexandrite at 780 nm, 250-microseconds pulse duration, 8 Hz, and a 4-mm spot size. A spectrum of welds was obtained from 1- to 20-W/cm2 average irradiance. Weak welds occurred with no thermal damage obtained at lower irradiances: stronger welds with thermal damage confined to the weld site occurred at higher irradiances. At still higher irradiances, local vaporization occurred with failure to "weld." Thus, there was an optimal range of irradiances for "welding," which varied inversely with dye concentration. Histology confirmed the thermal damage results that were evident clinically. IG dye-enhanced laser welding is possible in skin and with further optimization may have practical application.

Transfusion-associated graft-vs-host disease in patients with malignancies. Report of two cases and review of the literature.

Graft-vs-host disease can develop in immunosuppressed individuals who receive blood-product transfusions that contain immunocompetent lymphocytes. We report two cases of fatal transfusion-associated graft-vs-host disease that developed in patients with Hodgkin's disease who were undergoing therapy. We review all cases of this entity in patients with malignancies, represented predominantly by patients with hematologic malignancies. The groups at risk for development of transfusion-associated graft-vs-host disease, the clinical presentation and course, and methods of diagnosis are summarized. Prevention of this highly fatal condition is possible by irradiation of blood products given to patients at risk, but problems remain in determining the groups that warrant such measures. Dermatologists need to have heightened awareness of this entity to facilitate more complete diagnosis and allow establishment of effective standards of care.

Yellow nail syndrome.

The yellow nail syndrome is characterized by yellow, slow-growing nails in association with lymphedema, idiopathic pleural effusions, chronic bronchiectasis, and chronic sinusitis. We report two patients with yellow nail syndrome in whom spontaneous clearing of the nail changes occurred without resolution of the respiratory involvement. This observation suggests that nail changes may not result from the systemic manifestations. We also report for the first time the histopathologic findings of the nail matrix and bed, which demonstrate dense, fibrous tissue replacing subungual stroma with numerous ectatic, endothelium-lined vessels that are similar to that in the pleura in yellow nail syndrome. We hypothesize that primary stromal sclerosis may lead to lymphatic obstruction, thus explaining the clinical manifestations.

Primary cutaneous aspergillosis mimicking dermatophytosis.

We recently reviewed a skin biopsy specimen obtained from a child with acute monocytic leukemia that demonstrated abundant mycelia present within a keratin plug of a hair follicle, a granulomatous dermal inflammatory infiltrate, and focal dermal invasion by fungi. These histologic findings were suggestive of an invasive dermatophyte infection; however, Aspergillus flavus was identified by culture. This case illustrates the need for care in interpreting biopsy specimens of cutaneous fungal infection in the immunocompromised host, since proper treatment is determined by the specific agent present. The morphological features of fungi in tissue sections and histopathologic patterns of host response in the immunocompromised patient may be misleading in trying to identify fungal pathogens. At present, culture is the most reliable method for identifying pathogenic fungi and should be utilized to confirm appropriate therapy.

Bactericidal action of carbon dioxide laser radiation in experimental dental root canals.

The ability of a carbon dioxide laser to sterilize the root canal of human teeth has been investigated. Three oral bacteria, Streptococcus sanguis, Streptococcus mutans, and Actinomyces viscosus, and three other bacteria, Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa were used as experimental organisms. Exposure of cells on glass slides to laser radiation showed there was little difference in the exposure required to kill these six organisms. Complete recovery of bacteria from the root canal was initially a problem and was only achieved when bacterial manipulations and removal were carried out in rapid succession, within 5 min of inoculation. However, the geometry of the instrumented canal and the laser alignment were major factors in achieving consistent cell death of oral bacteria in the root canals. Using sets of 10 teeth, four repeated exposures of 10 W for 1 s was found to sterilize 4 or more of the teeth.