Contact dermatitis from organophosphorus pesticides

Effect of chronic pesticide exposure in farm workers of a Mexico community

Pesticides are frequently used substances worldwide, even when the use of some of them is forbidden due to the recognized adverse effect they have on the health of not only the people who apply the pesticides, but also of those that consume the contaminated products. The objectives of this study were to know the health issues of farm workers chronically exposed to pesticides, to evaluate possible damage at genetic level, as well as to explore some hepatic, renal, and hematological alterations. A transversal comparative study was performed between 2 groups, one composed of 25 farm workers engaged in pesticide spraying, and a control group of 21 workers not exposed to pesticides; both groups belonged to the Nextipac community in Jalisco, Mexico. Each member of both groups underwent a full medical history. Blood samples were taken from all farm workers in order to obtain a complete blood count and chemistry, clinical chemistry, lipid profile, liver and kidney function tests, erythrocyte cholinesterase quantification, lipid peroxidation profile, and free DNA fragment quantification. For the information analysis, central tendency and dispersion measurements were registered. In order to know the differences between groups, a cluster multivariate method was used, as well as prevalence reasons. The most used pesticides were mainly organophosphates, triazines and organochlorine compounds. The exposed group showed acute poisoning (20% of the cases) and diverse alterations of the digestive, neurological, respiratory, circulatory, dermatological, renal, and reproductive system probably associated to pesticide exposure. More importantly, they presented free DNA fragments in plasma (90.8 vs 49.05 ng/mL) as well as a higher level of lipid peroxidation (41.85 vs. 31.91 nmol/mL) in comparison with those data from unexposed farm workers. These results suggest that there exist health hazards for those farm workers exposed to pesticides, at organic and cellular levels.

An update on airborne contact dermatitis: 2001-2006

Reports on airborne dermatoses are mainly published in the context of occupational settings. Hence, in recent years, dermatologists and also occupational physicians have become increasingly aware of the airborne source of contact dermatitis, resulting mainly from exposure to irritants or allergens. However, their occurrence is still underestimated, because reports often omit the term 'airborne' in relation to dust or volatile allergens. For the present update, we screened the journals 'Contact Dermatitis' (July 2000 to December 2006); 'Dermatitis', formerly named 'American Journal of Contact Dermatitis'; 'La Lettre du Gerda' (January 2000 to December 2006); and also included relevant articles from other journals published during the same period. This resulted in an updated list of airborne dermatitis causes.

Modulation of microvascular function following low-dose exposure to the organophosphorous compound malathion in human skin in vivo

This study investigates whether malathion, a widely used organophosphate insecticide, has its effects on cutaneous vasculature in healthy human volunteers through its anticholinergic activity or through the modulation of other, noncholinergic pathways. Acute, low-dose exposure to malathion (10 mg/ml for 5 h under occlusive dressing) caused a significant increase in cutaneous blood flux, monitored by using laser-Doppler flowmetry and imaging. It had little effect on tissue levels of ACh, nitric oxide, and histamine assayed in dermal dialysate collected from malathion-exposed and control-treated skin. The duration of the cutaneous vascular response to exogenous ACh (2%) delivered by iontophoresis was significantly enhanced by preexposure to malathion, both <1 h after its removal and 24 h later ( P < 0.001). At <1 h, the time to 50% decay of the response was 24 ± 4 and 50 ± 8 min in control and malathion-treated skin, respectively. Malathion also enhanced the size and duration of the axon reflex-mediated vasoresponse to ACh. The increase in blood flux to malathion and the endothelium-mediated response to exogenous ACh, both in the presence and absence of malathion, were attenuated by pretreatment of the skin with atropine and local anesthesia ( P < 0.01). We conclude that short-term exposure to a single low dose of malathion causes prolonged modulation of the physiological function of the cutaneous vasculature and that this is, in part, through its action on acetylcholinesterase at both neuronal and nonneuronal sites.