Maybe a product like this would help.
http://www.allergycontrol...3-free-clear-shampoo.aspx

The problem with health food store products can be those natural ingredients that they promote. Several of them like peppermint oil and menthol are known skin irritants. There is a general impression that natural products are the best but honestly extract of poison ivy is natural as well. Parabens ie. methylparaben, propylparaben etc... are preservatives that cause problems for some people. You may want to check the same site for shower head water filters. My friend got one and the itching scalp went away.
I hope you find something that works for you.

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