one thing we do is be very careful with washing powder find a sensitive one, ecover or something similar, which seems to aggravate it, and lots of rinses with no fabric conditioner, use clear vinegar in the fabric drawer. cotton clothes and bedding only, no feather stuffed things, we got silk stuffed pillows and duvet, mattress covers and we use a steamer a lot, we steam the mattresses regularly,we don't have curtains, soft furnishing gets steamed, we use a dyson animal vacuum, and wash the filters, this helps as it dust mites are defiantly a cause of the part of the allergies/sensitivities, we cut labels out of clothes.
I don't use any of the usual cleaning products in the house, stick to ecover, bicarbonate of soda , soda crystals, vinegar.
we do this because DD gets terrible eczema if we don't, if we keep the house free of harsh cleaning products' she stays eczema free, and it seems to help DH,
I get all shampoos and soaps from the health food shop, and we have noticed if anyone uses normal stuff in the house both DH and DD flare up,
DH always showers if he feels itchy as it helps,he takes antihistamine,
If he avoids yeast and wheat it helps, but we are not sure if this is a total allergy/intolerance,
as a baby and toddler DH apparently demanded to have his back tickled all the time.