4.5 year old son with asthma triggered by cold

My son has had eczema and multiple food allergies since he was six-month old. As I do not trust mainstream medicines, he had mostly been on homepathy for his eczema. He started off with pulsatilla 6c, then moved on to calc sulph for about 4 months - this was when he was about two years old. The combination brought some relief from eczema and food allergies. It also cleared off his nasal passage which used to be generally blocked before. Since his second birthday, I have noticed that he can tolerate pretty much all food except fish, nut and some outdoor triggers. However his eczema gets markedly worse at the onset of spring and stays high through summer. Last r we started a pulsatilla 200c combined with psorinum 200c (both once a week) for three months. Once his eczema cleared we stopped it (I am not sure honestly whether the medication cured it or it cleared on its own when summer ended). One other development which is again since his third birthday is asthma attack with colds. Almost every cold (especially this year)he gets during winter seems to develop into an asthma attack. So far, I have been able to keep the attack in check using nebulizer. I tried reviving the weekly pulsatilla 200c for his frequent colds and asthma but it seems to make it worse. I have noticed that pulsatilla 200c seems to actually bring about a cold (cough and stuffy nose) for a couple of days after I give him the dose. His eczema is also back now in spring - although it is definitely getting better with every passing year.

Constitution wise, he is an intelligent, gentle and talkative boy at home but is somewhat shy in external company. He is overwhelmed by big crouds and loud noise. He is also extremely attached to his family members and it is usually hard for him to adjust to new care givers.