High prevalence of immunoglobulin E (IgE) sensitization among sisal (Agave sisalana) processing workers in Tanzania.

PURPOSE: Allergic sensitization among workers exposed to sisal is scarcely documented. We examined whether sisal processing is associated with IgE sensitization and its relationship to the prevalence of respiratory symptoms among Tanzanian processors. METHODS: 138 sisal exposed workers and 78 non-exposed controls were skin prick tested (SPT) using dry sisal extract and fresh sisal sap. Sera from a subset of 43 participants were analyzed for total and sisal specific IgE. SPT wheal size, prevalence of positive SPTs and adjusted relative risk (RR) for sisal sensitization were determined and compared between exposed and controls. Prevalences for respiratory symptoms were compared between sensitized and non-sensitized sisal workers. RESULTS: Significantly higher prevalence of positive SPTs to sisal was found among 74 % of sisal workers compared to 17 % among controls. Compared to controls, the RR of sensitization to sisal was 4 times higher (95 % CI; 2.4-6.7) among exposed workers. All exposed workers had elevated IgE levels (>100 kU/l) and 27 % of tested sera had elevated sisal specific IgE. A high prevalence of respiratory symptoms was found in both sensitized and non-sensitized sisal workers. CONCLUSION: Sisal processing is associated with increased risk of IgE sensitization, but its clinical implication is not obvious.

[Purpuric contact dermatitis from Agave Americana]. / Dermatite purpurique de contact au suc d'Agave americana.

BACKGROUND: Irritant papulovesicular dermatitis after cutaneous exposure to the sap of Agave Americana, which contains chemical irritants such as calcium oxalate and saponins, is well known, but purpuric dermatitis is rare in such cases. CASE REPORT: We report the case of a 52 year-old man with purpuric dermatitis of the legs mimicking purpura vasculitis that appeared a few hours after he had cut down a large Agave with a chain-saw. DISCUSSION: Our case is quite similar to three other cases found in the literature. In all four cases the patients had been using machines causing projections of plant fragments (chain-saw, trimmer). This may have promoted vascular damage, either by direct traumatism or by embedding oxalate crystals and saponins in the skin close to small vessels.

[Contact dermatitis from Agave americana]. / Dermatitis de contacto por Agave americana.

Numerous plant species and their derivatives can cause skin reactions through a variety of mechanisms: irritative contact dermatitis, allergic contact dermatitis, contact urticaria and photodermatitis. We present a case of irritative contact dermatitis after exposure to the sap of Agave americana. The skin symptoms in this case have only been described on rare occasions; although this condition usually presents with a papulovesicular rash, in this patient it appeared as purpuric lesions in the contact area.