Photosensitivity is an abnormally high sensitivity to sunlight.
Most people are at risk of developing sunburn during long exposure to sunlight. Exposure to ultraviolet rays from the sun can also lead to skin damage and skin cancer. People who are photosensitive may develop a skin rash or severe burn even after limited exposure to the sun.
Some chemicals contribute to sensitivity to the sun. These can cause two different types of photosensitive reactions: phototoxic and photoallergic.
Phototoxic reactions are usually caused when a new chemical in the body interacts with ultraviolet rays from the sun. Medications are the most common cause of this type of reaction. Doxycycline and tetracycline, for example, can cause this reaction. The result is a skin rash that looks like a severe sunburn. These usually develop within about 24 hours of exposure to the sun.
Photoallergic reactions can also develop as a side effect of some types of medication. They can also develop because of chemicals found in products like beauty products and sunscreen. Photoallergic reactions to the sun tend to be delayed. It will usually take a few days for a rash to develop after sun exposure (Skin Cancer Foundation).
Several medical conditions, medications, and chemicals can cause photosensitivity.
Photosensitivity is a common side effect of various medications. These can include certain antibiotics, chemotherapy drugs, and diuretics.
Some medical conditions can also cause photosensitivity, including:
- Lupus erythematous: Lupus is a connective tissue disease. Red patches, lumps, and purple spots can develop on areas of the skin exposed to the sun.
- Polymorphous Light Eruption: According to the Skin Cancer Foundation, this condition usually occurs in women. People with this disorder can develop an itchy rash when they are exposed to the sun. As sun exposure continues and UV tolerance increases, symptoms generally appear less often.
- Actinic Prurigo: People with this condition may develop red bumps after sun exposure. These can turn into scaly patches. This disorder can occur year round even in the winter when sun exposure tends to be less.
Symptoms of photosensitivity vary from mild to severe. The most common symptom is an exaggerated sunburn or a skin rash. The rash may or may not cause itching. In some cases, the sunburn can be so severe that blistering develops. Weeping of the skin and peeling can also occur in severe cases.
The amount of sun exposure required for a reaction varies greatly. For some people, very little sun exposure can cause a rash or burn. Others may need prolonged exposure in order to have a reaction.
A diagnosis is made after a complete medical history. This includes a list of medications currently being taken by the patient. Doctors usually pay attention to the pattern of the rash and its timing with sun exposure. In some cases, a skin biopsy is recommended.
Treatment usually includes lower exposure to the sun.
Some chemicals can cause photosensitivity and should be avoided. These chemicals can be found in some medications and products. Medications that cause photosensitivity include some forms of chemotherapy. Sometimes, it’s not possible to avoid taking these medications.
When a skin reaction has already developed, treatments work to reduce discomfort and skin inflammation. These include some over the counter pain medications. Corticosteroid cream may be prescribed to decrease inflammation.
The best way to prevent symptoms of photosensitivity is to limit the amount of time spent out in the sun. People who are photosensitive should always use sunscreen when outside.
Covering and protecting the skin may also help prevent a reaction. People who are photosensitive can reduce symptoms by wearing hats, sunglasses, and long sleeves when outside.