Sun allergy can cause skin redness, itching, small red bumps or spots, and a burning sensation in the affected area. These symptoms occur due to an exaggerated immune reaction to sunlight and are most often noticed on the arms, hands, neck, chest, and face.
Although the exact cause of sun allergy is unknown, it may happen because the body recognizes sun-induced changes in the skin as unfamiliar, triggering inflammation.
This condition is usually prevented or reduced with regular sunscreen use and proper treatment guided by a dermatologist, which may include oral antihistamines.
Main symptoms
The main symptoms of sun allergy are:
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Red patches on the skin
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Blisters or small red spots on the skin
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Itching in one area of the skin
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Irritation and sensitivity in parts exposed to the sun
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Burning sensation on the skin
In some cases, fluid-filled blisters can form. This is more common in people with fair skin or those taking medicines that increase sensitivity to sunlight.
These symptoms can appear within minutes after sun exposure, and depending on a person’s sensitivity, the time can be even shorter.
How to confirm a diagnosis
A dermatologist diagnoses sun allergy by observing symptoms, reviewing medical history, and performing light-sensitivity tests, such as phototesting or photopatch testing, where ultraviolet light at different wavelengths is used to check the skin’s reaction.
Another possible test is a contact test, which involves applying substances to the skin followed by UV radiation to see whether they cause sensitivity when exposed to light. The doctor may also order other exams, such as blood tests or a skin biopsy, mainly to rule out conditions with similar symptoms, such as eczema or lupus.
An appointment with a nearby dermatologist can be scheduled using the tool below to investigate the possibility of sun allergy.
Possible causes
The exact cause of sun allergy is not fully known; however, several factors may contribute to its development, such as:
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Very fair, sensitive skin
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Use of chemical products on the skin, such as perfumes, insect repellents, or certain substances in sunscreen
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Use of medicines that cause sun sensitivity, such as tetracycline, sulfonamides, or ketoprofen
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Chemotherapy for cancer treatment
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Other skin diseases, such as dermatitis or psoriasis
People with a family history of sun allergy may also have a higher chance of developing skin changes after sun exposure.
Treatment options
Treatment for sun allergy should be guided by a dermatologist and begins with strategies to limit prolonged sun exposure, such as applying sunscreen and wearing sun-protective clothing that covers most of the skin.
In milder cases, a doctor may recommend oral antihistamines, such as loratadine or fexofenadine hydrochloride, to help relieve itching, or creams or lotions containing calamine or colloidal oatmeal to soothe the skin.
In more severe cases, a dermatologist may prescribe corticosteroid medicines, such as prednisone, hydroxychloroquine, or treatment with phototherapy.
How to protect the skin from the sun
To protect the skin and prevent the onset or worsening of sun allergy symptoms, the following measures are important:
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Avoid sun exposure by seeking shade and spending as much time as possible out of direct sunlight
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Apply sunscreen with a minimum SPF of 30 before leaving home
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Use a hydrating lip balm with SPF 30 or higher
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Avoid sun exposure during peak heat hours, between 10 AM and 4 PM, when sunlight is strongest
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Wear sun-protective clothing with at least UPF 40, or choose long-sleeved shirts and pants; in summer, opt for natural, lightweight, light-colored fabrics
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Wear a cap or hat and sunglasses to protect the head and eyes from sunlight
When sun allergy symptoms appear, apply cold water to the area and keep the skin out of the sun to reduce inflammation and ease itching and redness. A small amount of colloidal oatmeal lotion can also help calm the skin.
In severe cases with intense itching and widespread red patches, hospital care or a dermatology visit is recommended.