Tracy M. Katz

Insect repellents: Historical perspectives and new developments

Arthropod bites remain a major cause of patient morbidity. These bites can cause local or systemic effects that may be infectious or inflammatory in nature. Arthropods, notably insects and arachnids, are vectors of potentially serious ailments including malaria, West Nile virus, dengue, and Lyme disease. Measures to curtail the impact of insect bites are important in the worldwide public health effort to safely protect patients and prevent the spread of disease. The history of insect repellent (IR) lends insight into some of the current scientific strategies behind newer products. Active ingredients of currently available IRs include N,N-diethyl-3-methylbenzamide (DEET), botanicals, citronella, and, the newest agent, picaridin. Currently, the Environmental Protection Agencys registered IR ingredients approved for application to the skin include DEET, picaridin, MGK-326, MGK-264, IR3535, oil of citronella, and oil of lemon eucalyptus. DEET has reigned as the most efficacious and broadly used IR for the last 6 decades, with a strong safety record and excellent protection against ticks, mosquitoes, and other arthropods. Newer agents, like picaridin and natural products such as oil of lemon eucalyptus are becoming increasingly popular because of their low toxicity, comparable efficacy, and customer approval. Various characteristics and individual product advantages may lead physicians to recommend one agent over another.

Consensus Recommendations on the Use of an Erbium‐Doped 1,550‐nm Fractionated Laser and Its Applications in Dermatologic Laser Surgery

BACKGROUND Nonablative fractional photothermolysis has revolutionized the way we treat a number of common skin conditions with laser technology. OBJECTIVE A comprehensive guide is needed for clinicians using this technology to treat specific skin conditions in various skin types. MATERIALS AND METHODS Recommendations were made from a recent round table discussion among experienced physicians and a review of recent literature findings. RESULTS Optimal laser parameters are dependent on patient skin type and condition. We recommended guidelines for the successful treatment of several common skin conditions on and off the face using nonablative fractional photothermolysis. Specific conditions were dyschromia, rhytides, acne scars, surgical scars, melasma, and striae distensae. CONCLUSIONS We developed reproducible guidelines to most effectively treat a variety of skin types and conditions using nonablative fractional photothermolysis. Future large, multicenter trials are indicated for further optimization of treatment parameters. Reliant Technologies paid travel expenses and honorariums to all authors.

Fractional Photothermolysis for the Treatment of Postinflammatory Hyperpigmentation

Postinflammatory hyperpigmentation (PIH) is an acquired hypermelanosis of the skin. Development of PIH can occur after any type of inflammation of the skin but is typically seen in association with acne, folliculitis, eczema, and trauma and as a complication of laser resurfacing. Other diseases that may produce this change are lichen planus, lichenoid drug reaction, lupus erythematosus, fixed drug reaction, pityriasis rosea, herpes zoster, insect bite reactions, contact dermatitis, and superficial burns. It is thought that inflammatory interruption of the epidermal–dermal junction is responsible for the development of PIH and that the degree of inflammation and disruption of the epidermal–dermal junction affects the severity of the PIH. Arachidonic acid metabolites and histamine, found in large amounts in inflamed skin, may play a role in the initiation of the development of PIH. Histopathology reveals high levels of epidermal melanin, with melanophages present in the superficial dermis. Lymphohistiocytes are variably present around superficial blood vessels in the dermal papillae. Clinically, lesions appear as irregularly shaped, darkly pigmented macules that coalesce and may persist for months or become permanent. PIH is more commonly seen in people with darker skin types and is found equally in men and women. PIH can occur anywhere on the body and at any age. Resulting cosmetic disfigurement may lead to problems with self-esteem, social interactions and to distress. Treatments for PIH include topical agents such as retinoids, hydroquinone bleaching creams, corticosteroids, dermabrasion, and chemical peels. 6 These treatment modalities have been used with varying success. Topical hydroquinones have been associated with undesirable depigmentation, irritant dermatitis, and ochronosis. Chemical peels and microdermabrasion may cause dyspigmentation and hypertrophic scarring. The Q-switched ruby laser has been used for the treatment of PIH with variable results and for postsclerotherapy hyperpigmentation. Owing to the success of fractional photothermolysis in treating epidermal and dermal pigmented lesions and conditions, it was conjectured that PIH could also be treated with this technology.

Nonablative Fractional Photothermolysis for the Treatment of Striae Rubra

Fractional photothermolysis has proven to be an effective treatment modality for hypopigmented and acne scars. Striae distensae may be considered to be a form of dermal scarring. It was hypothesized that fractional photothermolysis with the 1,550-nm erbium-doped fiber fractionated laser (Fraxel, Reliant Technologies Inc., Mountain View, CA) may be an effective treatment modality for this type of dermal scarring. In the early stages of the condition, changes are more inflammatory in nature, appear purple to red, and are called striae rubra. More advanced lesions, called striae alba, are hypopigmented and atrophic. We report the successful treatment of striae rubra using fractional photothermolysis. To our knowledge, these are the first reported cases of fractional photothermolysis for the treatment of striae rubra.

Fractional photothermolysis for the treatment of surgical scars.

Surgical scars are commonly treated using additional surgical revisions. The pulsed dye laser (PDL) can be used to palliate erythema, and the 1,450-nm diode or 1,320-nm neodymium-doped yttrium aluminum garnet (YAG) laser can be used to improve atrophy. Carbon dioxide (CO2) and erbium-doped (Er) YAG lasers benefit atrophic scars but are ablative and therefore associated with long recovery periods and many side effects. There is demand for a treatment that is noninvasive and addresses multiple scar characteristics simultaneously (erythema, atrophy, height, dyspigmentation).

595-nm long pulsed dye laser and 1450-nm diode laser in combination with intralesional triamcinolone/5-fluorouracil for hypertrophic scarring following a phenol peel

Hypertrophic scars and keloids are a therapeutic challenge because of the low response to treatment and recurrences after treatment. A variety of treatment regimens have been used with different degrees of success, with no universally accepted treatment protocol resulting in their complete and permanent resolution. We offer this case to demonstrate a combination approach for the treatment of hypertrophic scarring. A 75-year-old woman (with Fitzpatrick skin type II) presented with a 4-month history of scarring, which had developed following a phenol peel for perioral rhytides. The patient underwent 10 treatment sessions with the 595-nm long-pulsed dye laser followed immediately by the 1450-nm diode laser in combination with intralesional triamcinolone and 5-fluorouracil. After the fifth treatment session, about 90% improvement was noted; at the last treatment session, greater than 95% overall improvement was noted. Two and a half years after the last treatment session, the patient and treating physician noted no regression. A limitation of this therapy is that the combination approach makes it difficult to determine what individual contributions each treatment modality had on the final result. We have illustrated a successful multifaceted treatment regimen for hypertrophic scars and keloids using a combination approach.

Dermatosis Papulosa Nigra Treatment with Fractional Photothermolysis

Dermatosis papulosa nigra (DPN) is a benign skin condition characterized by multiple, small, hyperpigmented macules and papules found on the malar areas of the face, neck, and trunk. It is almost always seen in the black population. Prevalence of DPN in the black population has been reported to be between 10% and 35%, with many patients noting a family history of the lesions and the number of lesions increasing with age. Histologically, DPN is the same as seborrheic keratosis (acanthotic type).

Nonablative fractional photothermolysis for facial actinic keratoses: 6-month follow-up with histologic evaluation

BACKGROUND A number of epidermal and papillary dermal skin conditions can be treated safely and effectively with fractional photothermolysis (FP). OBJECTIVE We sought to evaluate the effectiveness of FP with a 1550-nm fractionated erbium-doped fiber laser for the treatment of facial actinic keratoses (AKs). METHODS Fourteen men, ages 59 to 79 years, underwent 5 laser treatments (2- to 4-week intervals) at an energy fluence of 20 to 70 mJ and treatment level of 11 (8-10 passes), corresponding to 32% to 40% surface area coverage. AK counts and photographs were taken at baseline, before each treatment, and at 1-, 3-, and 6-month follow-ups after the last treatment. Biopsies were performed at baseline and at the 3-month follow-up. The clinical improvement of the actinic lesions was evaluated by a dermatologist using digital photography and lesion counts at all 3 follow-up visits. RESULTS The AK count for each patient was reduced on average by 73.1% (67.5%-77.7%) at the 1-month, 66.2% (60.0%-71.5%) at the 3-month, and 55.6% (43.9%-64.8%) at the 6-month follow-up visit. Excluding two cases, all biopsy specimens (baseline and at the 3-month follow-up) were positive for histologic features of AK and/or squamous cell carcinoma. LIMITATIONS This study is limited by a small number of patients; therefore further clinical studies are warranted. CONCLUSIONS FP decreases the number of clinical AKs; however, posttreatment biopsy specimens indicate the histologic persistence of AKs (epidermal tumors). FP is not an adequate single-treatment modality for AKs.

Fractional Photothermolysis: A New Therapeutic Modality for Xanthelasma

Xanthelasma of the eyelid is an asymptomatic and not uncommon disease with cosmetic consequences that drive the patient to seek medical treatment. tic acid cauterization, carbon dioxide laser ablation, erbium :YAG laser treatment, pulsed-dye laser treatment, and Q-switched Nd:YAG laser treatment. 1-7 .

Herpes Zoster in the Distribution of the Trigeminal Nerve After Nonablative Fractional Photothermolysis of the Face: Report of 3 Cases

Herpes zoster is a viral eruption caused by reactivation of the varicella zoster virus (VZV). After primary infection or vaccination, the virus remains latent in the dorsal root ganglion until it is reactivated, usually in older adults or immunocompromised patients. Herpes zoster lesions on the skin classically develop in a dermatomal distribution, following the pathways of the involved nerves. An outbreak in an immunocompetent host is characterized by unilateral dermatomal pain and an eruption of clustered vesicles.