allergies
"I had been taking Allegra and Nasonex for years, but still did not have good control over my allergies and asthma.  I used Benadryl as needed when my two prescription medicines were not enough.  The pulmonologist told me that Benadryl has an intense drying effect in your body and that it makes your mucous more viscous (thicker).  Within 2 days of starting Xyzal (and stopping Benadryl), I definitely had thinned mucous and my skin was much less dry.  My asthma was much better controlled and I had less sensitivity to environmental triggers.  Unfortunately, I also started experiencing moderate-to-severe headaches along with a feeling of depression/anxiety.  Without Xyzal, I get pneumonia.. with it, I feel crazy.  Works, but bad side effects."