Rhus Tox is based on a more natural method for minmizing alergic reaction similar to the way orthodoxy uses steroidal pills and or injections. Rhux Tox can be gotten at a health food store, usually comes in a small bottle that contains a whole bunch of tiny white pills. You will find it sold in different concentrations, like 2X, 6X and 4X. Aside from knowing that 6X is more concentrated than 2X, I do not understand how the user is to make best use of this information. I have a couple bottles, one is 2X, one is 4X, and they both include the same basic instructions that really does not tell much information about the X. The pills are made up in part by tiny doses of the same kind of offending substance found in poision ivy - called Urushiol.
Doseage:
It is generally advised to take the pill by disolving it under or on the tongue. There are two basic methods for using Rhus Tox: 1) as a preventative; 2) to treat an existing condition. As a preventative, the basic idea is to take a single dose twice a day (once in morning, once in evening) for a week, then repeat after 30 days. Each dose generally should be 1 pill (for children) or 2 (for adults). This method helps build up some natural tolerance/resistance. This does not guarantee that a condition will never onset for a given person, but if it does, the condition will generally be minimized by having built up the resistance ahead of time. Everybody tends to be a bit different, some people are more or less senstive to this or that. For some people the preventative method may help avoid a rash all together, for other people, they may not avoid it completely but when they do get a rash it will generally be less severe.
For somebody with an existing condition/rash, the doseage advised is to start out taking 1 dose every 2 hours (adults - 2 pills, children - 1 pill) for 4 doses then continue dosing by increasing the duration between doses, like every 3 hours, then every 4 hours. Based on the instructions that came with my bottle, it sort of assumes that the condition will begin to subside with this approach, during which the interval between doses is to be continually increased (up to 5 or 6 hours or more) and eventually the condition is gone.
Using vinegar as a wash/rinse is supposed to help reduce itching. Likewise, Sasafrass tea can also be used as a rinse/wash. Rinse/wash the area where the rash is present (the blisters) and the itching should subside. Drinking Sasafrass tea should also help internally detoxify.
A week ago at a farmers market a woman told me that she uses lye soap when she gets poison ivy and claims this drys up the condition within a day. I have lye soap, made it myself, but never knew it could provide this kind of benefit. Of recent years I've done pretty good job avoiding an outbreak of poison ivy rash but it was not long ago that I used to get it reeeeeeeaaly bad, so I sympathize with your child.