to think it’s some sort of a mystery illness

[Sunisshiningagain]

about 18 months ago son had a bout of itchy skin for about 3 months then it went away.
a year later i suffered with it for about 6 months. Now husband is going through it.
Scabies is what comes in mind but it would not have gotten better without medication for me and son??
Any other ideas?
have other children at home without symptoms

Eczema? It comes and goes with my son…he struggled with it last winter, then it was completely gone over the summer and he has a flare up again now, only a small patch of skin.

As pp suggested it could be eczema or it could be an over reaction to something you normally use such as wash powder or shower gel if it's not rinsed enough. It won't be scabies as that is tiny mites burrowing under your skin and needs strong medication to get rid. They don't just disappear like fleas.

Hmm i’m not convinced it’s just ‘eczema’
the itch was so intense that i had blood tests etc as couldn’t sleep or function properly.
and the fact that 3 of us have gone through it in the space of 18 months with identical symptoms. The trigger is heat. When the skin is covered up, especially at night, the itch intensifies

Hives?

There is something nothing on the skin visible and it’s still itching like mad.
Sometimes there are hives

Scabies wouldn't have got better without medication.

That’s what google told me too but i still feel itchy sometimes but nowhere near as bad it was a few months ago

Impetigo

I've had intensely itchy skin for a year now. Finally saw a derm yesterday. I do have a history of eczema but this presents in every way more like an allergy. I have been taking Fexofenadine twice daily for a few months. It got very, very bad last November and was all over my entire body except my face, hands and soles of feet.

Intensely itchy in the evenings and at night and like you, heat triggers it.

I have managed to work out that any products containing paraffin make it much worse. I've had on and off eczema my whole life but have just learned that this is not uncommon as paraffin is a 'sealant', it traps moisture in but it doesn't allow the skins to breath. Switching to Cataphil has helped. All the emollients the GP prescribes were making it worse. Derm has ordered blood tests finally.

I'm sure you have already thought about what may have changed - laundry, home fragrances etc..