within a week of taking doxycycline i had a rash which got worse in the heat, as i was taking it as an anti malerial drug for my travels. the instructions says to avoid sunlight.. this is stupid and impossible if you are traveling to a tropical country for a holiday. other side effects i noticed were my face was swollen , i had puffy eyes and constant itching of my skin.these symptoms disappeared 24 hours after i stoppd taking these tablets.