Is a person with sensitivity to hazel nuts usually sensitive to all nuts of the same family? to the best i can recall when i have them i get very sick

Not necessarily.: Allergies can be specific to a single type of nut. However, nuts are usually mixed, either in recipes or in processing plants, so from a practical perspective it may be hard to truly know if you have an isolated hazelnut allergy.

Allergy vs : intolerance to nuts, you can just be intolerant or allergic to one type of nuts.True allergy symptoms to any kind of food are usually pronounced and can be elicited by challenge and are reproducible, that's of course under supervision of an allergist. Cross reactivity of hazel nuts to other types of nuts is common. Better see an allergist/immunologist, check acaai.org for an allergist in your area