Sun allergy: what is it, causes and what can you do

Sun allergy is an abnormal skin reaction to sun-exposed skin (such as face, arms, neck, legs) when someone is exposed to sunlight. The most common form of sun allergy is polymorphic light eruption (PLE), other forms include urticaria solaris (hives or hives due to sunlight), photodermatitis, juvenile spring eruption (non-itchy blisters or bumps on the auricles in young children, in the spring). It is more common in women than in men, up to 3-4 times more. It usually begins between the ages of ³⁰ and ⁴⁰, and on average more often in Western countries.

What are the skin complaints?

The skin reactions can arise “suddenly” at any time, while people used to be able to withstand the sun well. The skin symptoms can look different. With the first strong rays of the sun in spring, sun-exposed skin parts such as arms, face and coeur, itchy skin bumps, blisters and redness. These reactions only occur a day (sometimes up to 5 days) after exposure to UV rays and without being preceded by a sunburn reaction such as pain and redness. Without further exposure to sunlight, the skin will heal in 7 to 10 days. Sometimes severe reactions can even spread to the covered skin.

What are the causes of sun allergy?

Hypersensitivity is caused by ultraviolet (UV) radiation from the sun or tanning bed. There are two different UV radiation, UVA and UVB radiation.

UVA rays are present with relatively equal intensity during all daylight hours throughout the year, and can penetrate clouds and glass. These UVA rays make up the largest part of the ultraviolet radiation, so more than UVB.

UVA mnemonic: A for Alwayspresent, Agingskin and Asymptomatic(no skin burn).

UVB radiation penetrates into the superficial epidermis and is responsible for our vitamin D productione. So for a slow and longer lasting tan. Too much UVB causes redness, sunburn and eventually also skin aging and skin cancer. Unlike UVA, UVB does not penetrate glass.

UVB mnemonic: B for Burn– sunburn and tan

UVA Radiation is now considered the main cause of PLE.

Read more about both of these UV rays.

Other factors

Hypersensitivity to sunlight can also result from internal diseases. Lupus erythematosus is the best known example. There are two forms of lupus erythematosus, one with skin lesions only (cutaneous discoid lupus erythematosus – CDLE) and one with additional complaints from other organs, especially joints (systemic lupus erythematosus – SLE).
Medicines: water tablets, painkillers, antibiotics, anti-itch medication. More on medication and light.

Plant species such as: Vegetables/herbs/fruits: Anise, Celery, Citrus fruits (particularly bergamot, lime and lemons) Dill, Parsnip, Parsley, Fig and Carrots. Hogweed, Buckwheat, Angelica, Chervil, Lace Flower, St. John’s wort and rue

Cosmetics: some chemical sunscreens can provoke it. Chemical sunscreens containing paraaminobenzoic acid (PABA), cinnamates, benzophenones, dibenzoylmethanes, camphor derivatives, oxybenzone.
Perfume (musk ambrette (all), 6-methyl coumarin, sandalwood oil and phototoxic reactions to bergamot oil, peru balsam)

HOW IS THE DIAGNOSIS MADE ?

A trick as to whether the reactions are caused by UVB or UVA can be determined fairly well by answering the following questions.

Do the skin reactions occur when you:

1.Use of sunscreen
2. behind glass
3. in the shade
4. Light cloud cover

All four yes, means it is probably UVA. All four no indicates UVB.

The diagnosis can often be made on the basis of the patient’s story and skin reactions. Occasionally it is necessary to use light tests to determine whether UVA, UVB or visible light causes the skin reactions.

What can you do yourself?

Sunlight habituation & sunscreen

In the spring, gradually accustom the skin to the sun. During the initial period use a good protective mineral sunscreen with zinc oxide and titanium dioxide in it. These two ingredients must be in a sunscreen, titanium dioxide covers UVB well and zinc oxide protects the skin against UVA rays and part of the visible light. With PLE, UVA protection is so important. An SPF higher than 30 is good.

– Avoid the sun between 11 a.m. and 3 p.m. when the sun is brightest.
– Wearing loose clothing with long sleeves and a wide-brimmed hat or cap.
– When sitting or lying still, the effect of the sun is greater than when walking or cycling.
– Wet skin is more sensitive to sunlight.
– Snow and sand reflect a lot of sunlight; little water and grass.
– Even under the parasol, a lot of sunlight (particularly UVA) reaches the skin.

Learn more about chemical and mineral sunscreen filters.

The Iconic Elements Day Cream is enriched with a natural UVA filter, derived from a carefully selected algae, and is perfect for daily care.

WHAT IS THE PROGNOSIS ?

Symptoms can vary in strength from year to year. Sometimes it worsens over the years, sometimes an improvement occurs spontaneously. In 30-50% of patients, the complaints are most severe in early spring and less so in summer. This is called light habituation. Autumn and winter period there are no more skin reactions.

Literature

Lembo S, Raimondo A. Polymorphic Light Eruption: What’s New in Pathogenesis and Management. Front Med (Lausanne). 2018;5:252.

Fesq H, Ring J, Abeck D. Management of polymorphous light eruption : clinical course, pathogenesis, diagnosis and intervention. Am J Clin Dermatol. 2003;4(6):399-406.

Schleyer V, Weber O, Yazdi A, Benedix F, Dietz K, Röcken M, Berneburg M. Prevention of polymorphic light eruption with a sunscreen of very high protection level against UVB and UVA radiation under standardized photodiagnostic conditions. Acta Derm Venereol. 2008;88(6):555-60.

While you are here

Until recently, visible light was thought to be relatively inert compared to its spectral neighbors, ultraviolet and infrared radiation. However, it has recently been reported in the literature that visible light can cause redness in fair skin, and pigment changes in darker skinned individuals. More about the dark side of light