I have had similar reactions to crops where red spider mites are present so perhaps insects are the culprits!
> Date: Sat, 11 May 2013 22:10:44 -0700
> From: leo@possi.org
> To: pbs@lists.ibiblio.org
> Subject: Re: [pbs] lachenalia bulbs and skin itch
>
> Lorraine wrote
>
> > We have been harvesting lachenalia and a number of other kinds
> > of spring flowering bulbs,... We've nearly been driven mad with
> > itchy skin and itchy lumps/welts, even on those parts of the
> > body which are covered by clothes.... we need to find a way to
> > protect ourselves and our workers from being adversely affected
> > by what we've been told are Calcium oxalate raphides
> > (needle-like, microscopic calcium crystals).
>
> Your experience does not sound right for calcium oxalate. Itchy lumps and welts suggest
> an allergic reaction to something. I would guess something other than the Lachenalia is
> causing the trouble. Calcium oxalate is carried in the sap and would only affect parts
> of the body directly exposed to the sap, either directly from the plant or transferred
> from the hands to the other body parts. In addition, most adult gardeners have
> sufficiently tough skin on our hands that calcium oxalate crystals should cause little
> trouble. I have never had any skin reactions after handling Lachenalia nor aroids such
> as Caladium and Dieffenbachia, which are known for having calcium oxalate in the sap.
>
> I am not familiar with Australian flora nor fauna that might cause allergic reactions;
> you might contact other Australian gardeners to see whether this is a recognized
> problem. Immune reactions are caused by antibodies, present in the person, directed
> against a particular foreign substance such as a protein from another organism.
> Reactions may occur in parts of the body not directly exposed to the substance because
> antibodies and white blood cells involved in the immune reactions are carried in the
> blood. Several species of Rhus ("poison ivy, poison sumac") present in the US are famous
> for causing such reactions. Immune reactions generally do not occur on the first
> exposure to the substance because the body needs to become sensitized after the first
> exposure and produce antibodies, which takes some time.
>
> Leo Martin
> Phoenix Arizona USA
>
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