Why Am I Suddenly Allergic To The Sun?

A few hours of sun exposure, and you notice that your arms and neck are covered in an itchy, bumpy rash? Could it be that you’ve become allergic to sunshine?! It might seem strange but several different things can make your skin react to the sun. In this blog, we take a closer look at what might be causing your photosensitive rash.

What can look like an allergic reaction to the sun occurs when exposed skin reacts to the UV light in sunshine and breaks out in a rash. We’re talking about direct sunlight on skin, not heat rash or a reaction to sweat that can occur when you get overheated, so it involves areas of the body that are on show: usually the head, arms, legs and upper chest. And, unlikely though it can seem, sunlight can indeed cause immune system responses, leading to irritation of various kinds on exposed skin.

The most likely suspect: polymorphic light eruption 

One in ten people in the UK suffer to greater or lesser extent from the condition called polymorphic light eruption (PMLE for short). It tends to affect light-skinned people, often women between 20-50, whose skin is super sensitive to the UV light in sunshine. PMLE often occurs right at the beginning of summer (or, more distressingly, on the first day of a beach holiday) in people who live somewhere, like the UK, where there isn’t much sun over the winter months, and newly-exposed skin isn’t used to the bright light.

PMLE can look very different on different people; it can show up as a rash, as pimples, pinpoint spots, discoloured plaques, irritated skin, or bullseye spots. The common characteristic is that it occurs on exposed skin.

There’s a serious variant of PMLE called actinic prurigo (also known as hereditary PMLE), which runs in families, and can affect children, which is rare in classic PMLE. It particularly affects people of indigenous American backgrounds, from both the North and South Americas.

Solar urticaria

This is very similar to - though rarer than - PMLE, in that it occurs in a similar demographic and under similar circumstances; the main defining characteristic of solar urticaria is that it causes hives, rather than dermatitis-like symptoms. The hives can last a few minutes or a few hours, so are generally shorter-lived than PMLE, but it can, in extreme cases, be accompanied by headaches, wheezing, nausea or low blood pressure.

Other conditions

There are some rare conditions that can involve photosensitivity, which can feel like an allergy to the sun. These include the autoimmune disease Systemic Lupus Erythematosus (SLE), where sufferers sometimes present with a characteristic inflamed ‘malar’ or butterfly rash on the face, and cutaneous porphyrias, where the skin erupts in painful blisters after sun exposure.

Rosacea in all its forms also involves photosensitivity, in that it is exacerbated by exposure to sunlight.

Chemical photosensitivity

Another reason for a reaction to sunshine is that the sufferer has come into contact with a substance that increases their skin’s sensitivity to sunlight, with the effect that their skin can react strongly with rashes or blisters if it’s exposed to the sun. This could be something they’ve eaten, drunk or taken as medication, or something (chemicals or poisonous plants, for example) their skin has touched and then been exposed to sunshine. 

In these situations, it’s not so much a case of being allergic to sunshine, but being allergic or having a reaction to some other substance, which is activated by sun exposure. 

For more information about polymorphic light eruption, see our article How Is Polymorphic Light Eruption Treated?

Although creams and balms cannot ‘cure’ or treat the cause of PMLE, they can provide a bit of relief for affected skin, softening thickened areas and keeping skin in good healthy condition.

Our products do not contain sunscreens! Do not apply oils or oil-based balms like Skin Salvation to exposed areas of skin in bright sunlight, as the oils can make the skin more likely to burn.

Recommended products:

Balmonds Skin Salvation
with hemp and beeswax

Balmonds Daily Moisturising Cream
with shea butter and calendula

Balmonds Cooling Cream
with shea, menthol, aloe vera & lavender

Polymorphic light eruption

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