Sun allergies are very common, especially among young women and people with fair skin. This article looks at the causes and symptoms of PLE and other reactions to the sun, as well as explaining how to prevent sun allergies and protect allergy-prone skin.
Sun allergies How can I help prevent PLE and protect my allergy-prone skin?
What is a sun allergy and what are the symptoms?
Sun allergies, also known as photodermatitis, are an immune system reaction to sunlight which most often appears in the form of an itchy red rash.
The most common form of sun allergy is polymorphous light eruption (PLE), also known as polymorphic light eruption (PMLE), with ‘polymorphic’ referring to the fact the condition can appear in various forms.
The symptoms of PLE range from a mild, bumpy rash through to skin redness, pustules and blisters, with the skin nearly always itchy regardless of the skin’s appearance. PLE normally appears on areas of skin which have been newly exposed to sunlight, such as the underside of the arms and chest, and the backs of hands, legs and feet. Facial skin can be affected, but this is less common.
These areas of skin are commonly covered by clothing in winter, and therefore many polymorphous light eruption sufferers often experience symptoms each year when skin is first exposed to strong sunshine, or when visiting countries with warm temperate climates.
In some cases just 30 minutes of sun exposure is enough for issues to arise, although for most people their sun allergy rash develops over the course of several hours. The rash normally clears within a week upon no further sun exposure, but failure to do so may result in a worsening of sun allergy symptoms.
What causes sun allergies and PLE?
Direct sun exposure triggers sun allergies and PLE due to its UV light component. Similarly, symptoms can also be triggered by indirect light exposure such as that from sitting by a window or from wearing thin clothing outdoors.
Exactly how these triggers cause PLE is not fully known but research suggests that it may be due to an inherited genetic disposition. When people have the underlying condition, their immune system identifies areas of skin altered by the sun and reacts against this which causes a rash:
- UV light rays – especially long wavelength UVA rays (which trigger PLE in 80% of people affected) – penetrate deeply into the skin where they can damage cells.
- UV-induced free radicals form highly reactive chemical compounds which cause oxidative stress, resulting in cell damage.
- People with PLE have an impaired cellular defense which reduces their skin’s ability to handle these free radicals.
- On exposure to the sun their skin responds by over activating its immune function, resulting in red and inflamed skin.
Some medications such as antibiotics and antihistamines are also known to cause skin sensitivity which can exacerbate symptoms in sun allergy sufferers. If you are concerned that your medication may be influencing your PLE, seek advice from your doctor or other relevant medical professional.
Find out more about how sun affects skin in general in How do UVA, UVB and HEV light rays affect skin.
Treatment and prevention for sun allergies and PLE
Whilst there is no cure or treatment to get rid of sun allergies such as polymorphous light eruption, symptoms can be prevented or reduced by careful sun protection. Limit your exposure to the sun by avoiding the peak hours when it is at its most intense, wear protective clothing, and use a sun protection product that offers high or medium protection against UVA, UVB and HEV light, and that has been specially formulated for your skin type and condition.
Sunscreen should be applied generously prior to sun exposure, and should be reapplied frequently to ensure your skin’s protection, especially after swimming, perspiring or towelling.
You can read more about how to minimise the risks of exposure, how to choose the right sun protection products for your skin and how best to apply them in 'how should I protect my body from the sun?'
Eucerin Sun Creme-Gel Sun Allergy Protect SPF 50 and SPF 25 is a light, non-sticky creme-gel sunscreen that has been specially formulated for skin prone to sun-induced allergies such as PLE. Eucerin’s Advanced Spectral Technology combines broadband and photostable UVA/UVB filters1 with Licochalcone A to neutralise free radicals caused by UV and HEV light. The formula also contains Alpha-Glucosylrutin which helps to prevent sun-induced allergies and is unperfumed to minimise the risk of skin irritation. It can be used on both your face and body.
For those with severe PLE, a dermatologist may recommend a topical steroid cream or a course of prophylactic light therapy (also known as ‘photo hardening’ or `desensitisation`). This treatment gradually exposes skin to UV rays in order to build up a tolerance of sunlight.
Those with milder PLE often find that the condition gradually improves as the skin becomes more resistant to sunlight, and over time it may even disappear completely.
- Meeting the high standards for UVA and UVB protection defined by Cosmetics Europe. The levels of UVA protection are higher than the EU recommendation.