In polymorphic light eruption, itchy bumps, blisters, or excessive redness and swelling typically appear in early spring (with the first sun exposure) on sun-exposed areas such as the arms and face. The skin reactions often appear in the evening or night after sun exposure but can also develop later. In more severe reactions, the lesions can spread. Often, there is a cyclical pattern: symptoms begin in the spring, decrease over the summer, disappear in autumn and winter, and return the following year. The intensity of symptoms can vary yearly, and the condition usually resolves on its own after several years.
Symptoms
In polymorphic light eruption, the following usually appear:
- Itchy bumps, blisters, or excessive redness and swelling on areas exposed to the sun, such as the arms and face.
- Skin lesions typically appear in the afternoon or evening after sun exposure, although they can also develop later.
- In more severe cases, lesions can spread to other parts of the body.
- Often, there is a cyclical pattern: symptoms begin in the spring, decrease in the summer, disappear in the fall and winter, but return the following year.
- The intensity of the symptoms can vary each year, and in most people, they disappear spontaneously after a few years.
How is photosensitivity diagnosed?
Dermatologists can diagnose polymorphic light eruption based on the patient’s medical history and the observed skin reactions.
In cases of doubt, light exposure tests may be performed to determine whether sunlight is a factor and which wavelength (UVA or UVB) is causing the reactions.
Allergy tests can also be performed to identify substances (cosmetics, plants, medications) that cause photosensitivity in combination with light.
If necessary, blood tests, urine tests, stool tests, or skin biopsies may be performed to detect or rule out underlying diseases.
What is the treatment and what can be done?
- Avoid triggers: Known causes, such as certain medications, should be avoided.
- Gradually get the skin used to sunlight: Gradual sun exposure in early spring or summer can help the skin adapt, become thicker, and produce pigment, which provides some protection.
- Use sunscreen: Sunscreens that offer protection against UVA and UVB light with an SPF of at least 15 are recommended.
- Corticosteroid creams: These can relieve symptoms once they appear.
- Light therapy: The skin may be gradually exposed to artificial light (UVA or UVB) under medical supervision.
- Medications: In severe cases, systemic medications may be prescribed.
Sunscreens
Sunscreens protect against UV light. A sunscreen with SPF 15 allows a person to stay in the sun 15 times longer before burning.
For adequate protection, apply sunscreen in a thick enough layer and reapply regularly, especially after swimming or sweating a lot.
Other measures
If sun exposure and sunscreen are not enough to control photosensitivity, it is important to avoid sunlight as much as possible. This includes seeking shade, wearing protective clothing, and hats.
