hi ! any skin allergies cannot be cured with antihistamines ( allegra, atarax etc) even if they are taken for a life time, they just help ur body in stopping excess histamine stimulation and give u temporary relief, there are definite causes which cause such excess stimulation in body and they differ from person to person, in some it might be due to food, in some it might be due to dust or in some it might be hormones. homoeopathy has definite cures for such conditions.
Next Steps
you need to consult perosnally a good homoeopath in ur vicinity and share your details, it helps in finding the cause and removing it through medicines.
Health Tips
avoid things that might be causing your skin allergy