Phototoxicity: what it looks like and how to avoid it

What if a pill or a cream made your skin act like you’d spent hours in the sun after only a few minutes outside? That’s phototoxicity. It’s a non‑allergic reaction where a chemical (often a medicine) plus sunlight causes an exaggerated sunburn. It can be painful, fast, and obvious — so knowing the signs and what to do can save you a lot of trouble.

What causes phototoxicity and how it shows up

Many common drugs can cause phototoxic reactions. Think tetracycline antibiotics (like doxycycline), some fluoroquinolones, amiodarone, certain diuretics, and a few nonsteroidal anti‑inflammatories. Even topical agents — like some retinoids or fragrances — can sensitize skin. Plants can too (limes and celery are classic offenders).

Phototoxicity usually appears on skin exposed to sunlight: redness, sharp borders where clothing covered skin, swelling, blistering in severe cases, and intense pain or stinging. It often shows up quickly after sun exposure and is dose‑related — the more drug + sun, the worse the reaction. That’s different from photoallergy, which is immune‑driven, can spread beyond exposed areas, and may take longer to appear.

How to protect yourself and what to do if it happens

First, check labels and ask your pharmacist when you start a new medication. If the drug warns about sun sensitivity, plan ahead. Practical steps work well: use broad‑spectrum sunscreen SPF 30 or higher, reapply every two hours, wear a wide‑brim hat and long sleeves, and avoid the sun between 10 a.m. and 4 p.m. Glass and windows may block some UV, but not all, so be careful during long drives or near reflective surfaces like water and snow.

If you get a phototoxic reaction, treat it like a bad sunburn at first: cool compresses, loose clothing, and over‑the‑counter pain relievers if they’re safe for you. Topical steroid creams can reduce inflammation for moderate reactions. Importantly, contact your prescriber — you may need to stop or switch the medication. Seek urgent care if you have large blisters, fever, or signs of infection.

Photoallergy requires different testing and care, so if your rash spreads beyond sun‑exposed areas or keeps coming back long after sun exposure, mention that specifically to your doctor. For future prevention, keep a list of drugs that caused reactions and share it with every healthcare provider.

Short, practical rule: if a medicine lists sun sensitivity or you notice unusual burning or blistering in the sun, assume higher risk and protect your skin. It’s a small step that prevents a lot of pain—and keeps your treatment on track without surprises.

Angus MacAlister 31 July 2023
Voriconazole and Phototoxicity: An Overview

Well, folks, let's dive right into the sunny world of voriconazole and phototoxicity - it's a real beach party! Now, voriconazole is an antifungal medication, quite a hero in the medical world. But every superhero has its kryptonite, and for our friend voriconazole, it’s phototoxicity. This means that voriconazole can make your skin super sensitive to sunlight, turning a simple sunbath into a potential scene from a lobster horror movie. So, next time you're popping voriconazole, remember to slap on that sunblock, or you might end up redder than a tomato at a salsa convention!