Summer is in full swing and while spending time at the beach, pool or working on a tan is at the top of many people’s to-do lists, sun safety may not be. July is National Ultraviolet (UV) Safety Awareness Month and pharmacists play a vital role in sun safety and medication advice year-round.
Photosensitivity is defined as an abnormal, exaggerated response to UV exposure, potentially leading to the development of sunburn that occurs when the skin is exposed to UV sources, such as sunlight or tanning beds. In addition, there are several prescription and OTC medications that can cause photosensitivity.1
Because excessive sun exposure and sunburn can lead to premature aging, wrinkles and an increased risk of skin cancers such as melanoma and basal cell carcinoma, it is imperative that patients are aware of the drugs that cause photosensitivity and that pharmacists are able to administer effective patient education regarding the prevention and treatment of sunburn.2
Causes and clinical manifestations
Several prescription and OTC medications have been shown to cause photosensitivity. Both topical and systemic medications can cause photosensitivity. Some of the most notable classes of drugs that cause photosensitivity include nonsteroidal anti-inflammatory drugs (NSAIDs), antimicrobials, cardiovascular agents, tretinoins, and antineoplastic agents.3
The following list provides some examples of common medications that cause photosensitivity:3
- Oral Contraceptives
- First generation antihistamines
- antineoplastic drugs
- Thiazide Diuretics
- Tricyclic Antidepressants
Photosensitivity reactions usually present as sunburn. Sunburn is an acute inflammatory reaction of the skin to UV radiation.
Erythema is often seen as a result of vasodilation of blood vessels in the dermal layer of the skin. The signs and symptoms of sunburn usually develop as a delayed response to sun exposure; however, erythema is often observed after a short period of sun exposure.
Symptoms of a mild to moderate sunburn include redness, skin that feels warm, swelling, itching, pain, blisters, and/or chills. Severe sunburns require immediate medical attention, depending on the severity of symptoms, such as syncope, hypotension, fever, or dehydration.4
Prevention and treatment of photosensitivity reactions
The mainstay for preventing drug-induced photosensitivity reactions is sun protection. Sun exposure protection includes avoiding direct sunlight, wearing protective clothing when exposed to sunlight, and most importantly, using broad-spectrum sunscreens appropriately.
The FDA recommends water-resistant sunscreen, with an SPF of 30 or higher, for protection against UVA and UVB rays when exposed to active sunlight. The application should be generous and reapplied with a frequency of at least every 2 hours while outdoors and reapplied after participating in water activities.3
Patients should be aware that skin color, amount of sunscreen applied and frequency of application will affect exposure to UV radiation. Sunscreen should be used as directed, but more frequent application may be warranted depending on conditions such as swimming and/or heavy sweating.
In addition, patients should be aware that UV rays can be stronger when reflected from water, sand and snow. When patients expect to be outside for long periods of time, they should seek shade, especially during peak times of 10 a.m. to 4 p.m., and wear protective clothing, such as hats, long-sleeved shirts, pants, and sunglasses, if shade is not available.3 It is also recommended for all patients, especially those at risk for photosensitivity, to wear sunscreen with an SPF of 15 or higher on a daily basis, regardless of expected sun exposure.
If sunburn occurs, treatment regimens vary based on the mechanism of the photosensitivity reaction, but most are phototoxic when the drug is induced. Mild phototoxic reactions are usually self-limiting and can be treated symptomatically without medical intervention.
Common treatments include cool compresses, cool showers or baths, emollients such as aloe vera, and oral pain relievers.4 Local anesthetics such as benzocaine should be avoided because of the potential for causing a contact allergy. However, if there is a mild photoallergic reaction, the treatment is similar to a contact allergy; topical corticosteroids should be applied to the affected areas to reduce itching and inflammation.3
Patients with severe sunburn who also have systemic symptoms, including headache, fever, dehydration, and vomiting may require referral to a physician or hospitalization. These patients may receive fluid replacement, parenteral analgesics, and/or empirical antibiotic therapy.
The role of the pharmacist
As pharmacists, we act as first-line providers of patient information. Given the large number of drugs that can cause photosensitivity, patients taking any of these drugs should receive safety advice, especially during the summer months.
In addition, because drug-induced photosensitivity remains an often underdiagnosed clinical problem, patients should be educated about the clinical signs and symptoms associated with photosensitivity reactions. Education about sun exposure protection is essential for preventing drug-induced photosensitivity reactions.
You should always consider UV exposure based on season, geographic location, altitude and weather conditions. Educational tools, such as websites and smartphone apps that indicate local weather and/or UV levels, are available to help determine what type of protection is most essential and when to avoid sun exposure.
Through good education, we can help patients avoid the risk of photosensitivity reactions and enjoy their favorite summer activities.
- Photosensitivity and your skin. Skin Cancer Foundation. https://www.skincancer.org/risk-factors/photosensitivity/. Accessed July 5, 2022.
- Skin cancer facts and statistics. Skin Cancer Foundation. https://www.skincancer.org/skin-cancer-information/skin-cancer-facts/. Accessed July 5, 2022.
- The sun and your medicine. US Food and Drug Administration. https://www.fda.gov/drugs/special-features/sun-and-your-medicine. Published September 25, 2015. Accessed July 6, 2022.
- sunburn. Johns Hopkins drug. https://www.hopkinsmedicine.org/health/conditions-and-diseases/sunburn. Accessed July 5, 2022.