Doxycycline, a type of antibiotic, can make your skin more sensitive to sunlight. It's important to avoid excessive sun exposure, including sunlamps and tanning beds, while taking doxycycline and for a few days after stopping treatment. If you must be in the sun, it's best to wear protective clothing and use a broad-spectrum sunscreen with a sun protection factor (SPF) of at least 30. If you develop a skin rash, hives, or any other skin reaction after sun exposure, contact your doctor immediately.