Medicines for Polymorphic light eruption

What it is

Polymorphic light eruption (PLE) is a common skin condition in which an itchy rash develops on skin exposed to sunlight. It is essentially a reaction of the skin to ultraviolet (UV) light (from the sun, and sometimes artificial UV), and is sometimes called a "sun allergy", though it is not a true allergy. It is one of the most common sunlight-related skin conditions, and is more common in women and often begins in younger adulthood. The rash typically appears within hours to a couple of days after sun exposure, on areas that have been exposed (such as the arms, chest, or legs, and sometimes the face), and — as the name "polymorphic" (many forms) suggests — it can look different from person to person, appearing as small itchy red spots or bumps, raised patches, blisters, or other forms; it is usually itchy, and sometimes has a burning feeling. It characteristically occurs in spring or early summer, or at the start of a sunny holiday, when the skin is first exposed to stronger sunlight after a period of less exposure, and it often improves as the summer goes on and the skin becomes more used to (or "hardened" to) the sun. Each episode usually settles within a few days to a week or so if further sun exposure is avoided, and it typically heals without scarring. PLE is not dangerous, but it can be uncomfortable and can recur each year, affecting enjoyment of sunny weather and holidays. It is usually managed with sun protection and simple measures, and, for those more troubled by it, other treatments (including, for some, treatments to build up the skin’s tolerance to sunlight) can help. The key messages are that PLE is a common, itchy, sunlight-triggered rash that is not dangerous, that it often improves through the summer as the skin adjusts, and that sun protection and gradually building up sun exposure help manage and prevent it.

How it is treated

Polymorphic light eruption is managed with sun protection and simple measures to treat and prevent the rash, with additional treatments for those more troubled by it. When the rash occurs, it usually settles within a few days to a week or so if further sun exposure is avoided, and simple measures relieve symptoms: soothing treatments and, for itching, antihistamines or, if advised, a short course of a steroid cream can help; keeping the affected skin out of the sun while it settles helps it clear. The main focus, however, is on prevention, since PLE is triggered by sunlight and tends to recur: protecting the skin from the sun is central — using a high-factor, broad-spectrum sunscreen (that protects against both UVA and UVB) generously and reapplying it, wearing protective clothing and a hat, and being careful with sun exposure, particularly in spring and at the start of a sunny holiday when the skin is most likely to react. Gradually building up sun exposure, rather than suddenly exposing skin to a lot of sun, can help the skin become more tolerant ("hardened") over time, which is often why PLE improves as the summer progresses; introducing sun exposure carefully and gradually can reduce reactions. For people who are more troubled by PLE — for example with severe or frequent episodes, or a significant impact on their life — additional options are available and can be discussed with a doctor or dermatologist: these can include a course of carefully controlled UV light treatment (phototherapy) given before the sunny season to build up the skin’s tolerance, and other treatments in some cases. It is worth seeing a GP if the diagnosis is uncertain, if the rash is severe or troublesome, or if it significantly affects life, both to confirm PLE (and exclude other light-sensitive conditions) and to access further treatment. The reassuring messages are that PLE is common and not dangerous, that it often improves through the summer as the skin adjusts, and that sun protection, gradually building up sun exposure, and simple measures manage and prevent it, with further treatments available for those more affected.