Did you know that some medications can make your skin more sensitive to sunlight? You may be surprised at the prescriptions mentioned in this article because they’re quite common. Chemicals within certain drugs undergo changes when exposed to the sun. Be aware of these 10 medications that cause photosensitivity.
What Is Photosensitivity?
Photosensitivity, also called sun allergy, is the result of an immune system reaction that occurs in the skin following sun exposure. Although, the exact mechanism is undetermined regarding these reactions, it’s supposed that the immune system recognizes certain components of the skin as foreign or non-self.
When this happens, the body activates an immune response as a defense mechanism. This defense is what produces the symptoms, such as inflammation, redness, and swelling. Other symptoms include, red rashes, small blisters, hives in severe cases, or itchy eruptions following exposure to sunlight.
These reactions, although annoying and uncomfortable, are usually self-resolving and don’t require treatment. The areas of the body most commonly affected by photosensitivity are the neck and upper chest, the arms and lower legs, the forehead, nose, lips, and the backs of the hands.
Reactions can be triggered by brief moments in the sun, and commonly present within 24 hours of exposure, but may take several days of continuous sun exposure to manifest.
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UVA And UVB Radiation
Certain people are more prone to photosensitivity than others. Wavelengths that fall within the 320-400 nm range (UVA radiation) are more apt to initiate drug-induced photosensitivity reactions. To a lesser degree, UVB radiation, in the 290-320 nm range, can also cause skin reactions. Sunlight in this range is responsible for sunburn, and non-melanoma skin cancer, including basal cell carcinoma.
UVA radiation penetrates deeply into the dermis of the skin, causing photo-aging, cellular DNA damage, and immune-suppression. It’s important to protect yourself from both types of UV radiation, if the skin can’t repair the damage caused by sunlight, cells within the skin can start to divide and multiply uncontrollably. This is how tumors develops.
There are two types of photosensitivity: photo-toxicity and photo-allergy. Photo-toxicity is a chemically-induced irritation of the skin following sun exposure that doesn’t involve the immune system.
The reaction it induces resembles an exaggerated sunburn, which is caused by a chemical absorbing into the skin topically, or reaching the skin systemically via an oral medication.
Chemicals in medications absorb sunlight, changing their molecular structure. Theses changes are what stimulate reactions. Fluoroquinolones and tetracyclines are two such drugs that produce photo-toxic effects. Surface contact with these chemicals can also cause photo-dermatitis or photo-allergy, also referred to as sun poisoning.
In cases of photo-toxicity, reactions are primarily contained within areas of the skin that have been exposed to sunlight, and usually clear once the drug is discontinued. Photo-toxicity is mainly associated with UVA radiation, but UVB radiation may also contribute.
Photo-allergy (sun allergy) manifests as a red, itchy rash on skin that has been exposed to sunlight. Polymorphic light eruption is the most common type of sun allergy. The condition can have a genetic component or be caused by medications, particularly drugs that are used topically.
Negative reactions occur from exposure to UV radiation, which alters the structure of the chemicals in particular medications. The immune system sees these altered chemicals as antigens. This causes an allergic reaction within the skin that produces the symptoms, which unlike photo-toxicity, can spread to areas that haven’t been exposed to sunlight.
Mild cases of photo-allergy often resolve without treatment, with more severe cases being treated with steroid pills or creams. Photo-allergic reactions resemble eczema and may become chronic. The symptoms of photo-toxicity generally resolve after the medication has been discontinued, whereas, photo-allergy can persist even after the drug is no longer being used.
- Small bumps and rashes
- Raised patches
- Swelling and inflammation
- Itching and redness
- Darkening of the skin
- Stinging and burning sensations
Medications That Cause Photosensitivity
Following the medications listed under each category, I will include whether the drugs are photo-toxic, photo-allergic, or both.
Tetracyclines, including tetracycline and doxycycline / Photo-toxic
Fluoroquinolones, including Cipro and Bactrim / Photo-toxic
2. Hypoglycemics (Diabetic Drugs)
Sulfonylureas, including glipizide and glyburide / Photo-allergic
3. Nonsteroidal Anti-Inflammatory Drugs (NSAIDS)
Ibuprofen (Advil and Motrin) / Photo-toxic
Naproxen (Aleve) / Photo-toxic
Ketoprofen / Photo-toxic and photo-allergic
Celecoxib / Photo-allergic
Hydro-chlorothiazide / Photo-toxic
Furosemide (Lasix) / Photo-toxic
5. HMG-CoA Reductase Inhibitors
Statins, including fluvastatin, pravastatin, simvastatin, lovastatin, and atorvastatin / Photo-toxic
Itraconazole / Photo-toxic and photo-allergic
Voriconazole / Photo-toxic
7. Neuroleptic Drugs (Antipsychotics)
Phenothiazines, including chlorpromazine, fluphenazine, perazine, perphenazine, thioridazine / Photo-toxic and photo-allergic
Isotretinoin (Accutane) / Photo-toxic
Acitretin (Used for psoriasis) / Photo-toxic
9. Chemotherapy Drugs
Methotrexate, oncovir, adriamycin, gemzar, and 5-FU / Photo-toxic
10. Cardiac Medications
Diltiazem, amiodarone, quinidine, and procardia / Photo-toxic
Drug-induced sun sensitivity occurs when chemicals in medications are exposed to sunlight, producing negative skin reactions. Reactions can result from both oral ingestion of a drug or from compounds that are using topically.
If you’re on medications that increase photosensitivity, be diligent in protecting yourself when outside. Cover up and always wear sunscreen. I keep a wide-brimmed hat in my car, and I can’t tell you how many times I’ve used it!
Are you on any medications that cause photosensitivity? Have you noticed that your skin is more sensitive to the sun? Let me know in the comments:)
(1) Merck Manual: Photosensitivity Reactions
(2) Drugs.com: Sun Allergy (Photosensitivity)
(3) Medscape: Drug-Induced Photosensitivity
(4) Cancer Council: How ultraviolet (UV) radiation causes skin cancer
(5) PubMed: Phototoxicity and photoallergy
(6) Mayo Clinic: Sun allergy
(7) MedicineNet: Sun-Sensitive Drugs (Photosensitivity to Drugs)
(8) verywellhealth: Sun Sensitivity During Chemotherapy