My dad developed a sun allergy after going on a specific antibiotic following a spider bite. Been too long for me to recall what the antibiotic was, but I remember him having to apply sunscreen for even under his clothes, long sleeves, pants, gloves and wide brimmed hat through out the summer. If memory serves, it lasted several months, quite a while after he was done with the treatment.

Also, I've only seen people mentioning Lyme disease, but Rocky Mountain spotted tick fever is another tick borne disease you don't want to catch. My understanding it's also one of the main reasons a biosafety level 4 facility is being built in Hamilton, MT [0]. Though, I had thought the facility had been built a long time ago.

[0] https://www.niaid.nih.gov/research/biosafety-labs-needed

Doxycycline? I thought that was a known side effect. My dermatologist warned me about it when I went on a course during the summer months. This was over a decade ago, maybe they stopped warning patients?

Doctors seem to forget to do that sometimes, or the patients miss it. Someone I knew was put on a three month course and got a unusual sunburn, later I googled doxycycline and realized the likely connection.