皮肤科
27-07-2026
Photosensitizing Medications and Sun Exposure: Which Drugs to Avoid in Summer
出版日期: 07-08-2026
更新日期: 07-08-2026
主题: 皮肤科
预计阅读时间: 1 分钟
During the summer, with more time spent at the beach or at high altitudes, it is important to protect the skin from the sun's rays. High-SPF sunscreen, sunglasses with dark lenses, and hats are essential, but sometimes they are not enough to prevent skin or systemic reactions. In fact, many people are unaware that taking and/or applying photosensitizing medications can cause skin damage.
We discuss the topic with Dr. Michela Castello, dermatologist at the Vein & Derma Clinic, and Dr. Angela Tortorici, hospital pharmacist at Istituto di Cura Città di Pavia.
Medications and Sun Exposure: Possible Reactions
Many commonly used medications are photosensitizing, meaning that they contain active ingredients that react when exposed to sunlight (both UVA and UVB rays), triggering unexpected skin reactions.
Dr. Tortorici explains: “When a photosensitizing medication interacts with sunlight, reactions can occur in 2 different ways: a phototoxic reaction or a photoallergic reaction.”
Phototoxic Reaction
“A phototoxic reaction occurs because sunlight ‘activates’ the medication present in the body and increases its toxicity. This can result in a severe sunburn-like reaction, characterized by redness, blistering, and burning, which develops within a few hours of sun exposure on the areas of skin most exposed to sunlight. It is one of the most common drug-induced reactions.”
Photoallergic Reaction
“A photoallergic reaction, which is less common, involves a response by the immune system. Sunlight alters the structure of the medication, causing the immune system to attack the substance and trigger potentially severe skin reactions. These include hives and eczema, which may spread to areas of the body that were not exposed to sunlight and can develop even several days later.”
Which Photosensitizing Medications Can Cause These Reactions?
The main categories of medications to be aware of include:
- Antibiotics: tetracyclines (often used to treat acne) and fluoroquinolones (prescribed for urinary or respiratory infections) increase the skin's sensitivity to sunlight and therefore require appropriate photoprotection with sunscreen;
- Birth control pills and hormone therapies: estrogens do not cause true sunburn, but they can stimulate hyperpigmentation, increasing the risk of pigmentation changes and dark spots in predisposed individuals, such as melasma;
- Anti-inflammatory drugs (NSAIDs): ketoprofen (commonly found in gels and medicated patches for muscle pain) is one of the main medications associated with photosensitivity. When applied to the skin, sun exposure must be strictly avoided throughout treatment and for 2 weeks after treatment has ended. Oral naproxen and ibuprofen should also be used with caution;
- Antihistamines: paradoxically, medications used to treat allergies, particularly creams and gels applied to relieve insect bites, can cause phototoxic reactions, including blistering, when applied before sun exposure;
- Blood pressure and heart medications: certain diuretics, such as hydrochlorothiazide, and antiarrhythmic medications, such as amiodarone, can increase the risk of phototoxicity;
- Corticosteroids: particularly dexamethasone and beclomethasone, when applied to especially sensitive skin, may be associated with photosensitivity reactions that cause redness or irritation. In these cases, it is advisable to avoid sun exposure and to wait beyond the end of treatment before returning to normal sun exposure.
Corticosteroids are sometimes mistakenly considered phototoxic: they do not chemically react with UV radiation to cause direct cellular toxicity. However, some precautions are necessary when they are applied during the summer because they can make the skin thinner and therefore more vulnerable to damage caused by UV exposure.
It is also important to consider the risk of post-inflammatory hyperpigmentation following treatment for inflammatory skin conditions, such as eczema or insect bites.
Finally, caution is also recommended with certain supplements and herbal extracts, including St. John’s wort and berberine, which may increase the skin's sensitivity to sunlight.
How to Protect Yourself From the Sun Without Stopping Treatment
What should you do if you are taking medication? The most important rule is to never stop prescribed treatment on your own and to adopt a few sensible precautions.
Where possible, it may be preferable to take a once-daily medication in the evening, thereby reducing the concentration of the active ingredient in the bloodstream during the hours of greatest sunlight exposure. However, this does not completely eliminate the risk with long-acting medications.
It is essential to protect the skin with a broad-spectrum SPF 50+ sunscreen, reapplying it every 2 hours, and to stay in the shade as much as possible.