Venous anatomy and pathophysiology
Helane S Fronek in The Fundamentals of Phlebology: Venous Disease for Clinicians, 2007
Goldman and Fitzpatrick treated 30 female patients with leg telangiectasias less than 0.2 mm in diameter that were red in color. Of 101 telangiectatic patches, 13 were noted to have an associated reticular "feeding" vein between 2 and 3 mm in diameter, which was not treated. Seven patients with 25 patches of telangiectatic matting after previous sclerotherapy were also treated. Thirty-nine telangiectatic patches, chosen randomly, were treated with laser energies between 7.0 and 8.0 J/cm2 and compressed with a rubber "E" compression pad (STD Pharmaceuticals, Hereford, UK). FLDPL-induced hyperpigmentation completely resolved within 4 months. There were no episodes of cutaneous ulceration, thrombophlebitis, or other complications. However, hypopigmentation occurred in some patients with tanned skin. The laser impact sites usually remained hypopigmented for years, and in many cases this was thought to be permanent. With FLPDL treatment, the most effective fluence appears to be between 7.0 and 8.0 J/cm2. With these parameters, approximately 67% of telangiectatic patches completely faded within 4 months.
Skin
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
Melanosomes may be identified by characteristic immunostaining for tyrosinase activity or transmission electron microscopy (TEM). Hypopigmentation may be due to either an absence of melanocytes or an inability of melanocytes to produce melanin. Certain compounds that are chemically related to tyrosine and DOPA (i.e., precursors of melanin), such as p-tertiary butylcatechol, p-tertiary butyphenol, and hydroquinone, may cause hypopigmentation, while other chemicals may induce hyperpigmentation. 4-S-Cysteaminylphenol (4-S-CAP) exhibits selective cytotoxicity on follicular melanocytes in the black mouse, causing swelling and lysis of melanocytes, leading to the depigmentation of black hair follicles. Similar changes are not observed in albino mice, indicating that active melanin and tyrosinase synthesis are key to melanocytotoxicity of 4-S-CAP (Ito and Jimbow 1987).
Clinical Aspects and Differential Diagnosis of Atopic Dermatitis
Donald Rudikoff, Steven R. Cohen, Noah Scheinfeld in Atopic Dermatitis and Eczematous Disorders, 2014
In this late phase, the major features are pruritus, papulation, scaling, and lichenification usually involving the forehead, eyelids, upper lip (Figs 3.34–3.36), flexures of the neck, arms and legs, and the upper trunk (Fig 3.37). Dry, thick, extremely pruritic lichenified lesions are characteristic and prurigo nodules may sometimes be seen (Fig 3.37C). Poorly demarcated, these lichenified plaques range in color from a bright pinkish-red to a tannish-brown or grayish-brown in white people (Fig 3.38). Patients with darker skins may exhibit hyper- and hypopigmentation, as well as focal areas of depigmentation. Generalized xerosis is the rule with variable involvement of extensor surfaces and hands. Older patients may also have extensive head and neck involvement purportedly caused by exposure to aeroallergens and colonization by Malassezia sympodialis yeast forms.
Intense pulsed light treatment for Becker’s nevus
Published in Journal of Dermatological Treatment, 2021
Pin-Ru Wu, Lan-Jun Liu, Yi-Xin Zhang, Ying Liu, Xiao-Xi Lin, Gang Ma
The long-pulse lasers had been used for the treatment of hypertrichosis in BN. Long-pulsed alexandrite 755-nm laser without cryogen spray cooling was found to be reasonably efficacious minimizing both hyperpigmentation and hypertrichosis in a study of 11 patients who received 2–12 treatments (10). The 694-nm long-pulsed ruby laser effectively reduced hair density and pigmentation by 90% in a single case (11). While hypopigmentation and skin texture change were observed in some patients. The long-pulsed 808/810-nm diode lasers with low-fluence high-repetition-rate were used for hair removal of hypertrichosis in 15 BN patients, there was significant hair clearance at 6 months (score 3.9) and 12 months (3.5) without reduction of pigmentation (12). A case report of combination long-pulsed 1064nm Nd:YAG and 755-nm alexandrite lasers with skin cooling obtained a significant reduction in both hyperpigmentation and hypertrichosis (13).
A retrospective analysis of the influencing factors and complications of Q-switched lasers in tattoo removal in China
Published in Journal of Cosmetic and Laser Therapy, 2018
Mengli Zhang, Xiangdong Gong, Tong Lin, Qiuju Wu, Yiping Ge, Yuqing Huang, LiYu Ge
A variety of adverse reactions may occur during the laser treatment of tattoos (14), including pigmentation, hypopigmentation, bulla formation and allergic reactions (Figure 1). Therefore, it is necessary to communicate with the patients prior to treatment. The laser treatment of tattoos easily causes transient pigmentation and could be gradually alleviated in a few months, usually in patients who have type IV skin or patients who are exposed to the sun before and after the treatment. Therefore, postoperative sun protection and the administration of decolorizing agents should be emphasized. Hypopigmentation may occur after multiple treatments. Repeated treatment of the hypopigmented areas should be avoided, and the residual tattoos should not be subjected to further laser treatment until the skin is recovered from hypopigmentation. According to our experience, the recovery time for hypopigmentation is rather long. Generally, it takes 6 months to more than 1 year to achieve a complete recovery. Laser treatment may cause the formation of blisters and bullae, which are common for tattoos with high ink density or bright colors. If bullae form, patients may visit a hospital to have bulla fluid extracted. In addition, patients should apply topical moisturizing antibiotic ointments and avoid rubbing off the bulla wall.
Complications and posttreatment care following invasive laser skin resurfacing: A review
Published in Journal of Cosmetic and Laser Therapy, 2018
Dan Li, Shi-Bin Lin, Biao Cheng
After the first healing stage, at which point the acute inflammatory reaction has typically subsided or resolved wound healing gradually slows. Kim observed that hyperpigmentation occurred in 38.4% of 190 patients (skin type III and above) who received Er:YAG ablative LSR, with a mean onset and duration of 3.5 and 7.2 weeks, respectively, and with approximately 93.2% of cases exhibiting fading within 16 weeks. Approximately, 13.7% of the patients experienced hypopigmentation: its mean onset was 2 months after treatment, with fading occurring in 85% of the cases within 1 year(47). Graber reported a hyperpigmentation rate of 0.73% in patients who received fractional LSR; hyperpigmentation mainly occurred in patients with skin type III and higher. Scars sometimes manifested several months after treatment; these were rare but permanent. Occasionally, ocular damage, including cicatricial ectropion due to lower eyelid scarring, appeared late and required long recovery periods(48). Therefore, we termed this long healing period (3 weeks to 1 year) the chronic recovery stage.