Methyl Paraben May Increase Risk of Pruritus in African Americans Whereas Triclosan Is Inversely Associated With Pruritus and Eczema.

BACKGROUND: Phenols and parabens (P&Ps) are commonly found in skin care products. However, P&Ps' role in pruritus and eczema has not been studied. OBJECTIVE: The aim of the study was to investigate the association between P&Ps, and pruritus and eczema. METHODS: This is a cross-sectional population-based study of 2202 participants. We examined the association between urinary phenols (triclosan, bisphenol A, benzophenone-3) and parabens (methyl and propyl parabens) and itchy rash/eczema using the 2005-2006 National Health and Nutrition Examination Survey database. Phenols and parabens were divided into quartiles (Qs) with the first Q as the reference. We calculated odds ratios and 95% confidence intervals, adjusting for multiple variables. RESULTS: Urinary triclosan was inversely associated with itchy rash (P trend = 0.048). In a subpopulation analysis by race/ethnicity, urinary methyl paraben was positively associated with itchy rash in African Americans (fourth Q vs first Q: odds ratio, 12.60; 95% confidence interval, 1.03-154.06; P trend = 0.02). Triclosan was inversely associated with eczema in whites (P trend = 0.04). CONCLUSIONS: Methyl paraben exposure may increase the risk of itchy rash in African Americans, whereas triclosan may decrease the risk of itchy rash and eczema. The potential effect of triclosan and methyl paraben in pruritus and eczema warrants further study.

Urinary detection of corticosteroid in topical treatment of skin disease by 19F MRS.

OBJECTIVE: To investigate if it was feasible to quantify the renal excretion of topically applied corticosteroids by 19F MRS. MATERIALS AND METHODS: Five participants, one healthy and four with skin diseases, were treated with ointment containing betamethasone 17-valerate. Urine samples were collected for up to 87 h after the initial application. A sample of ointment mixed with urine served as a study control. Organic fractions were obtained after sample freeze drying, and resolved in deuterated chloroform prior to acquisition of 19F MR spectra at 470 MHz for typically 8 h. RESULTS: We detected fluorine signals in 40 of the 62 fractions of organic extracts. The corticosteroid was detected in samples from all patients, ranging from 0.1 to 2.8% of the applied steroid. No fluorine signal was obtained in samples from the healthy volunteer. DISCUSSION: 19F MRS can be utilized to detect topically applied corticosteroids in urine. However, more work is required to optimize and control for extraction procedures, complete spectral assignments and reliable quantification.

The disposition of chloroquine and its main metabolite desethylchloroquine in volunteers with and without chloroquine-induced pruritus: evidence for decreased chloroquine metabolism in volunteers with pruritus.

The pharmacokinetics of chloroquine and its main metabolite desethylchloroquine have been carried out in volunteers with and without chloroquine-induced pruritus. It was shown that the volunteers with pruritus tended to metabolize chloroquine slower than the volunteers without pruritus because the metabolic ratio was lower in the volunteers with pruritus than that in the volunteers without pruritus. However, the overall pharmacokinetic patterns were comparable between the two groups and agreed with published data. The 24-hour urinary collections in the two groups of volunteers indicated that the volunteers with pruritus excreted more chloroquine (although not statistically significant) than the volunteers without pruritus. This also indicates that they metabolized less chloroquine. There were no side effects of note in any of the volunteers. The volunteers who gave positive histories of chloroquine-induced pruritus had mild episodes of itching after intake of the drug; the pruritus subsided within 48 hours in all instances.

Pruritus during standardized mental stress. Relationship to psychoneuroendocrine and metabolic parameters.

The influence of experimentally-induced emotional stress on pruritic response of human skin was studied in healthy subjects. Experimental activation of the psychoneuroendocrine system was produced by standardized stressors, i.e. a colour-word-conflict test (Stroop-test) and a subsequent mental arithmetic problem. Pruritus was elicited by intradermal injection of histamine. Results obtained were compared with reported feelings of stress, and stress-induced physiological and biochemical changes. Reported stress levels were evaluated by a visual analogue scale. The physiological and biochemical observations included pulse rate, blood pressure, endocrine and metabolic parameters. The experimental model produced adequate psychoneuroendocrine stress reactions. Cutaneous responses to histamine remained despite this unaltered. The cutaneous responses were unrelated to reported stress levels as well as to physiological and biochemical variables prior to stressor exposure. The individual cutaneous reactions to stressor exposure were related to the adrenaline response pattern. Degree of control, ability to predict, and time limitation of the experimental situation may be important factors influencing the experimental outcome.

Urinary bile acids during development of recurrent cholestasis of pregnancy.

The pregnancies of two patients with mild intrahepatic cholestasis of pregnancy (RCP) were followed with detailed analyses of bile acids in urine. About twenty-five different bile acids were determined by GC/MS following separation according to mode of conjugation. The results were collated with the clinical course of the disease. The first detectable change in bile acid excretion was the appearance of tetrahydroxylated bile acids at about the 30th gestational week. Somewhat later and concomitant with the rise in urinary oestriol, the total bile acid excretion started to increase. In one of the patients, who had a maximum total excretion of 84 mumol/24 h, deoxycholic acid was a major constituent, comprising about 40% of the total. The same patient had only slightly elevated levels of tetrahydroxylated bile acids and serum amino-transferases. The possible effect of low-fat diet on these results is discussed. Monohydroxylated bile acids were present throughout the pregnancies in small amounts and their role as aetiological factors is discussed. The care of RCP patients is outlined, and the need for simple, specific and quantitative methods for following the course of RCP is pointed out.