Methylisothiazolinone in rinse-off products causes allergic contact dermatitis: a repeated open-application study.

BACKGROUND: In recent years, the prevalence of contact allergy to the preservative methylisothiazolinone (MI) has increased dramatically. Cosmetic products are one of the major sources of exposure. OBJECTIVES: To examine whether allowed concentrations of MI in cosmetic rinse-off products have the potential to cause allergic contact dermatitis. METHODS: Nineteen MI-allergic subjects and 19 controls without MI allergy applied two liquid hand soaps five times per day on areas of 5 × 10 cm(2) on the ventral side of their forearms. One soap contained 100 ppm MI, the maximum allowed concentration in cosmetics, and was used by 10 allergic subjects and all controls. Another liquid soap with 50 ppm MI was used by nine allergic subjects. As the negative control, all subjects used a similar soap that did not contain MI. The repeated open applications proceeded until a positive reaction occurred or up to 21 days. The study was conducted in a randomized and blinded fashion. RESULTS: Ten out of 10 MI-allergic subjects developed positive reactions to the soap with 100 ppm and seven out of nine reacted to the 50 ppm soap, while none of the 19 controls had a positive reaction during 21 days of application. No reactivity was seen to the soap without MI. The difference in reactivity to MI between MI-allergic subjects and controls was statistically significant (Fisher's exact test, P ˂ 0.0001). CONCLUSIONS: Rinse-off products preserved with 50 ppm MI or more are not safe for consumers. No safe level has yet been identified.

Lack of effect of the glucagon-like peptide-1 receptor agonist liraglutide on psoriasis in glucose-tolerant patients--a randomized placebo-controlled trial.

BACKGROUND: It has been proposed that glucagon-like peptide-1 receptor (GLP-1R) agonists used for the treatment of patients with type 2 diabetes might also improve their psoriasis. OBJECTIVE: To assess the efficacy and safety of the GLP-1R agonist liraglutide in glucose-tolerant patients with plaque psoriasis. METHODS: A total of 20 obese (body mass index > 25 kg/m(2)), glucose-tolerant patients with plaque psoriasis (psoriasis area and severity index (PASI) of at least 8) were randomized 1:1 to once-daily subcutaneous injections with liraglutide or placebo for an 8-week period. The primary end points were improvement in PASI and dermatology life quality index (DLQI). Secondary end points included changes in weight and high sensitive C-reactive protein (hsCRP) levels, as well as adverse events. RESULTS: After 8 weeks of treatment, no significant change in PASI was found in the liraglutide group (mean±standard deviation: -2.6 ± 2.1) compared with the placebo group (-1.3 ± 2.4) (P = 0.228). No difference in DLQI was observed between the groups [-2.5 ± 4.4 (liraglutide) vs. -3.7 ± 4.8 (placebo); P = 0.564]. HsCRP did not change in any of the groups (0.26 ± 1 (placebo) vs. 0.25 ± 2.2 (liraglutide); P = 0.992). Liraglutide treatment resulted in a bodyweight loss of 4.7 ± 2.5 kg compared with 1.6 ± 2.7 kg in the placebo group (P = 0.014) accompanied by decreased cholesterol levels. No serious adverse events occurred during the 8-week observation period. The most common complaint was transient nausea, which occurred in 45% of the liraglutide-treated patients but in none from the placebo group. CONCLUSION: Liraglutide treatment for 8 weeks did not significantly change PASI, DLQI, or hsCRP in a small group of glucose-tolerant obese patients with plaque psoriasis compared with placebo. A significant weight loss and decrease in cholesterol levels was observed in liraglutide-treated patients.

Improvement in psoriasis after treatment with the glucagon-like peptide-1 receptor agonist liraglutide.

A 59-year old man with moderate and stable psoriasis through 15 years was admitted to our Department with inadequately controlled type 2 diabetes. Treatment was initiated with the glucagon-like peptide-1 receptor (GLP-1R) agonist liraglutide. The patient experienced marked improvement in his psoriasis immediately after the start of liraglutide treatment. Itching stopped within days, scaling was reduced and spots of normal skin emerged. After 3 months, psoriasis was still improving. Excellent glycaemic control and a weight loss of approximately 8 kg over 3 months were moreover obtained. The patient had previously been well controlled in his diabetes without improvement in psoriasis, and the effect of liraglutide on psoriasis started before weight loss occurred. We discuss the possibility of a direct anti-inflammatory effect of liraglutide in psoriasis as well as indirect effects through improvement in comorbidities such as overweight. Randomized clinical trials are needed to reveal whether GLP-1R agonists represent a new therapeutic option for psoriasis.

The relation between sunscreen layer thickness and vitamin D production after ultraviolet B exposure: a randomized clinical trial.

BACKGROUND: Sunscreens absorb ultraviolet B (UVB) and it is a major concern that sunscreen use may lead to vitamin D deficiency. OBJECTIVES: To investigate the relation between the amount of sunscreen applied and the vitamin D serum level in humans after UVB exposure under controlled conditions. METHODS: Thirty-seven healthy volunteers with fair skin types were randomized to receive an inorganic sunscreen with sun protection factor (SPF) 8 of 0 mg cm(-2) , 0.5 mg cm(-2) , 1 mg cm(-2) , 1.5 mg cm(-2) , or 2 mg cm(-2) thickness on the upper body, approximately 25% of the body area. Participants were irradiated with a fixed UVB dose of 3 standard erythema doses 20 min after sunscreen application. This procedure was repeated four times with a 2- to 3-day interval. Blood samples were drawn before the first irradiation and 3 days after the last to determine the serum vitamin D level expressed as 25-hydroxyvitamin D(3) [25(OH)D]. RESULTS: The vitamin D serum level increased in an exponential manner with decreasing thickness of sunscreen layer in response to UVB exposure. For all thicknesses of sunscreen, the level of 25(OH)D increased significantly after irradiation (P<0.05), except for the group treated with 2 mg cm(-2) , in which the increase in 25(OH)D was not statistically significant (P=0.16). CONCLUSIONS: Vitamin D production increases exponentially when thinner sunscreen layers than recommended are applied (<2 mg cm(-2) ). When the amount of sunscreen and SPF advised by the World Health Organization are used, vitamin D production may be abolished. Re-evaluation of sun-protection strategies could be warranted.

Clothing reduces the sun protection factor of sunscreens.

BACKGROUND: Individuals are recommended to wait for 20 min following sunscreen application before dressing. However, this is probably seldom done in daily life, and therefore we investigated how dressing earlier than 20 min after application affected the sun protection factor (SPF). OBJECTIVES: To determine the SPF of a sunscreen applied at different amounts at 4, 8 and 20 min before dressing. METHODS: An organic sunscreen was used on the backs of 22 healthy volunteers. Before SPF testing, participants wore a cotton T-shirt for 60 min after the test areas had been uncovered for 4, 8 or 20 min after sunscreen application. The SPF was also tested on unclothed skin. RESULTS: The median SPF was 11.7 (2 mg cm(-2)), 5.7 (1 mg cm(-2)) and 3.3 (0.5 mg cm(-2)) for unclothed skin, and 8.1 (2 mg cm(-2)), 4.8 (1 mg cm(-2)) and 2.2 (0.5 mg cm(-2)) following an interval of 8 min before dressing. The SPF was similar for time intervals of 20 and 8 min when the amount was 1 mg cm(-2) (P = 0.48) and 2 mg cm(-2) (P = 0.56). For 0.5 mg cm(-2) there was no difference between skin clothed after 20 min and unclothed skin (P = 0.19), nor between skin clothed after 4 min and after 8 min (P = 0.28). CONCLUSIONS: When sunscreens are applied at amounts of 1 and 2 mg cm(-2) the time between sunscreen application and dressing can be as little as 8 min. When less sunscreen is used the SPF is insensitive to the length of time between application and dressing.

Pulsed dye laser vs. intense pulsed light for port-wine stains: a randomized side-by-side trial with blinded response evaluation.

BACKGROUND: Pulsed dye lasers (PDLs) are considered the treatment of choice for port-wine stains (PWS). Studies have suggested broadband intense pulsed light (IPL) to be efficient as well. So far, no studies have directly compared the PDL with IPL in a randomized clinical trial. OBJECTIVES: To compare efficacy and adverse events of PDL and IPL in an intraindividual randomized clinical trial. METHODS: Twenty patients with PWS (face, trunk, extremities; pink, red and purple colours; skin types I-III) received one side-by-side treatment with PDL (V-beam Perfecta, 595 nm, 0.45-1.5 ms; Candela Laser Corporation, Wayland, MA, U.S.A.) and IPL (StarLux, Lux G prototype handpiece, 500-670 and 870-1400 nm, 5-10 ms; Palomar Medical Technologies, Burlington, MA, U.S.A.). Settings depended on the preoperative lesional colour. Treatment outcome was evaluated by blinded, clinical evaluations and by skin reflectance measurements. RESULTS: Both PDL and IPL lightened PWS. Median clinical improvements were significantly better for PDL (65%) than IPL (30%) (P = 0.0004). A higher proportion of patients obtained good or excellent clearance rates with the PDL (75%) compared with IPL (30%) (P = 0.0104). Skin reflectance also documented better results after PDL (33% lightening) than IPL (12% lightening) (P = 0.002). Eighteen of 20 patients preferred to receive continued treatments with PDL (P = 0.0004). No adverse events were observed with PDL or IPL. CONCLUSIONS: Both the specific PDL and IPL types of equipment used in this study lightened PWS and both were safe with no adverse events. However, the PDL conveyed the advantages of better efficacy and higher patient preference.

The relation between sun protection factor and amount of suncreen applied in vivo.

BACKGROUND: The declared sun protection factor (SPF) is based on the use of a sunscreen layer of 2 mg cm(-2). However, only around a quarter (0 x 5 mg cm(-2)) of this amount is applied by sunbathers. Theoretical calculations have suggested that the effective SPF is related to sunscreen quantity in an exponential way but this was not confirmed in vitro and has not been studied in vivo. OBJECTIVES: To investigate the relation between SPF and sunscreen amount in vivo. SUBJECTS AND METHODS: On the backs of 20 healthy volunteers, five areas of 34 cm(2) each were marked. One area was phototested to determine the ultraviolet (UV) sensitivity. Four areas were treated with a sunscreen SPF 4 in different amounts: 0 x 5, 1, 2 and 4 mg cm(-2). Thirty minutes after sunscreen application a phototest was conducted on each area. The effective SPF was calculated 22-26 h after irradiation using the UV dose needed to produce just perceptible erythema (minimal erythema dose) on protected and unprotected skin. RESULTS: In all areas the mean SPF was significantly different from an SPF of 1 (no protection) (P

Durability of the sun protection factor provided by dihydroxyacetone.

BACKGROUND/PURPOSE: The sunless tanning agent dihydroxyacetone (DHA) is known to protect against longwave ultraviolet radiation (UVA) and visible light. Recently, our laboratory has shown that DHA in addition offers a modest sun protection factor (SPF) in humans. We conducted this study in order to investigate the durability of the SPF provided by DHA. METHODS: Ten healthy volunteers were treated with 20% DHA cream twice in three areas on the volar forearm. One, 5 and 7 days after the second application the participants were phototested with simulated sunlight in each area. Blue reflectance was used to measure the skin coloration by DHA in the test sites. RESULTS: DHA generated a significant SPF of 3.0 at day 1, 2.0 at day 5 and 1.7 at day 7 (P<0.0001). The SPF was positively correlated to the change in blue reflectance (r=0.39, P=0.034). The loss of SPF unit/day was not significantly different between the subjects (P<0.122). However, the intercepts were significantly different (P<0.0001) indicating differences in the initial SPF obtained among the subjects. CONCLUSIONS: The SPF of DHA decreases with the same loss of SPF unit/day between humans and the durability of the SPF thus depends on the initial SPF provided.