Contact allergy: another occupational risk to Tetranychus urticae.

BACKGROUND: Tetranychus urticae is a phytophagous, macroscopic mite ubiquitous to warm climates, which causes occupational allergic symptoms in farm workers. OBJECTIVE: This study was designed to investigate the cause and mechanisms of an otherwise "undetermined" recurrent and occupational dermatitis on the hands of farm workers and to obtain a better diagnostic profile of the urticaria that many farm workers who are allergic to T. urticae experience. METHODS: Fifty-six farm workers with occupational cutaneous and/or respiratory symptoms and 10 healthy farm workers underwent in vivo and in vitro diagnostic trials by skin prick testing, serum-specific IgE determination, and three different types of epicutaneous tests. RESULTS: Four of the 10 patients with recurrent dermatitis had a positive IgE reaction to T. urticae, and five of the 10 had a positive patch test response. The percentage of positive patch test responses between subjects with positive T. urticae IgE and those with negative T. urticae IgE was similar. The diagnostic trial allowed the diagnosis of immune-mediated contact dermatitis in seven of the 10 patients with recurrent occupational dermatitis on the hands. The result of the epicutaneous open test on healthy skin with no history of eczema was positive in almost all patients with IgE to T. urticae and episodes of occupational urticaria. CONCLUSIONS: Urticaria frequently occurring in farm workers allergic to T. urticae is an allergic contact urticaria. T. urticae is also directly responsible for recurrent dermatitis, caused by a different immune-mediated mechanism, in farm workers.

Effects of enzyme-potentiated desensitization in the treatment of pollinosis: a double-blind placebo-controlled trial.

Several controlled clinical trials have shown that specific immunotherapy (SIT) using incremental injections of allergens can be effective in the treatment of allergic rhinitis and asthma. Nevertheless, the risk of side effects have led to some recommended limitations of SIT. Enzyme-potentiated desensitization (EPD) is a proposed method for immunotherapy with very low doses of mixed allergens plus beta-glucuronidase enzyme, for which irrelevant or no side effects have been claimed. The aim of this study was to determine the clinical efficacy of EPD in the treatment of pollinosis. A double-blind placebo-controlled trial of EPD among 20 patients sensitive to Parietaria and grass pollen was performed. All patients recorded daily symptom scores for nine months following a single intradermal injection of EPD or buffered saline received in February. Symptoms recorded were nasal itching and obstruction, sneezing, rhinorrhea, itchy eyes and excessive tear production. Moreover, total and specific lgE were measured and CD3+, CD4+ and CD8+ peripheral blood lymphocytes were counted at different times. In the same period, ten additional subjects, with an allergic clinical profile similar to the subjects admitted to the double-blind trial, were studied in an open clinical trial in order to evaluate the effects of EPD without enzyme using a mixture of allergens. Symptom scores were higher in the placebo group (p < 0.001), with a similar level of significance for both global symptom score and for each individual symptom. Active-treated patients had a significant post-treatment increase in the mean percentage of T-CD8+ peripheral blood cells and a significant post-seasonal decrease in the mean percentage of Parietaria specific lgE. On the contrary, placebo-treated patients had a borderline significant post-seasonal decrease in the mean percentage of CD8+ circulating cells and a significant seasonal increase in the mean percentage of Parietaria specific lgE with no significant post-seasonal decrease. Finally, clinical results of the mixture of allergens injection were similar to those of the placebo in the double-blind trial. EPD injection caused only an asymptomatic, local wheal and flare lasting about two hours. Two patients (20%) in the active-treated group experienced a delayed, mild, unusual headache lasting about two days. In conclusion, EPD is clinically effective in the treatment of pollinosis. Some immunological modifications observed in the EPD-treated patients suggest an EPD-induced enhancement of tolerogenic mechanisms like "immune deviation."

Farm workers' occupational allergy to Tetranychus urticae: clinical and immunologic aspects.

A group of 46 farm workers (32 men), affected by a recurrent "occupational disease of undetermined origin", underwent an immunologic investigation with a Tetranychus urticae (TU) whole-body extract (TU-WBE) prepared in our laboratory. The patients suffered from seasonal attacks of rhinitis, during the summer and autumn periods, when working in open fields (30 subjects) or in greenhouse flower cultivation (16 subjects). In most patients, rhinitis was associated with bronchial asthma (16 subjects), urticaria (14 subjects), or both (three subjects). Allergic alveolitis or other common allergic diseases had been excluded, and a diagnosis of "occupational disease of undetermined origin" had been made before by other medical centers. Ten healthy farm workers and 10 atopic townsmen were chosen as control groups. An in vivo and in vitro diagnostic trial by skin prick testing (SPT) and serum specific IgE dosage with TU-WBE were done in all subjects. Thirty-six patients (78%) were found to be positive to both SPT and the IgE enzyme allergosorbent test (EAST), with a good correlation between IgE serum levels and cutaneous wheal size. Control groups did not show any reaction. The IgE-EAST homologous inhibition test was positive. The IgE-EAST cross-inhibition test excluded cross-reactivity between TU and Dermatophagoides pteronyssinus. The TU-exposure test was positive for the 36 patients with TU-WBE-specific IgE. Three patients who were negative for TU-WBE-specific IgE reacted to the TU-exposure test; in these patients, the scratch-chamber test (Finn chamber) with eggs and droppings from TU was positive.(ABSTRACT TRUNCATED AT 250 WORDS)

[The epidemiology of adverse reactions to nonsteroidal anti-inflammatory drugs. Nimesulide is tolerated by patients with adverse reactions to NSAIDs and modulates in man the skin response to histamine and codeine]. / Epidemiologia delle reazioni avverse ai farmaci antiinfiammatori non steroidei. La nimesulide è tollerata dai pazienti con reazioni avverse ai FANS e modula nell'uomo la risposta cutanea all'istamina ed alla codeina.

We evaluated the tolerance to NIM in patients with adverse reactions to NSAIDs, expressed by urticaria-angioedema, bronchial asthma or erythema polymorphous on 92 patients among which 32 atopics affected by asthma, rhinitis or contact dermatitis. Challenge test has been performed with increasing amounts of NIM per os every 2 hrs to a maximum of 100 mg/dose. The last dosage was repeated every 12 hrs for 4 times more. No reactions were observed in 86 patients (93.4%). Moreover we evaluated the efficacy of NIM in modulating pomphoid cutaneous reaction to histamine (HIS) and codeine (COD). Three subjects were prick tested with HIS and COD solutions at different concentrations (0.1 to 10 mg/ml), before and after a 5 days therapy with NIM at different dosages/kg/die. At NIM dosages of 3.7 and 2.7 mg/kg/die we observed a strong reduction of pomphoid activity of both HIS and COD. No clear effects were detected at 2.2 mg/kg/die dosage. We assume a dose-related in vivo inhibitory effect of NIM on cutaneous mast cells releasability or a direct anti-histaminic effect. We point out the possible therapeutic role of NIM in the treatment of allergic flogosis at steroid and cromon's side.