Are allergies bad for your health? if so, why do doctors recommend antihistamines? isn't that making the allergies worse while lessening the symptoms?

Allergy: Anti allergy agents include those that modify the allergic response ( steroids, leukotriene agonists, allergy immunotherapy ) and those that block histamine after the allergic response has been triggered. The antihistamines really work well at reducing the symptoms related to histamine. They do not make the allergies worse.

Usually: Allergic diseases adversely impact quality of life- hay fever having most impact leading to sleep disturbance, cognitive impairment, work/school absenteeism etc. Severe asthma and anaphylaxis can be deadly.Food allergy is a major burden for the patients especially when they are children. Antihistamine counteracts some of the histamine action but not the allergic reaction per se.

Agree with Dr. Chiu: Antihistamines give symptomatic relief but don't effect the course of allergies one way or another. Let me answer what I think you are getting at. In many diseases masking the symptoms is like a band aid and a mistake to not treat the underlying cause. Some people actually do get over allergies by themselves but not most. Allergy immunotherapy is the only treatment that affects the disease