Also known as LUCITIS, this occurs when skin is exposed to sunlight and is especially linked to UVA rays (hence the importance of a sunscreen which filters these efficiently – see chapter on “Sun creams”).
It is an immune defense reaction of the body in response to sun exposure.
The skin is covered with small spots or red patches (urticaria), which affect the chest and limbs but rarely the face. Lucitis can cause itching, which is sometimes severe.
It affects about 10% of the population and predominantly women. . Numbers have been rising over the last 20 years.
Certain sun allergies result from prolonged or repeated exposure to the sun. Therefore, it is vital to avoid the sun for several days. The signs of allergy should disappear of their own accord in less than 2 weeks.
There are several types of sun allergy:
- Benign Summer Lucitis: this predominantly affects women between the ages of 15 and 35. Most frequently, it appears a few hours after initial exposure to the sun. It causes small red pimples or blisters which are accompanied by itching.
It starts at the neckline and then reaches the shoulders, arms, back of the hands and legs. The face is rarely affected. Once treated, it can reappear after each new exposure to the sun. So it is essential to protect yourself from sun exposure for several days. The rash lasts for about a week and disappears if the affected person remains in the shade.
The allergy has a tendency to gradually disappear as the skin tans.
More often than not, summer lucitis occurs over several consecutive years (an unavoidable fact) and although sometimes it can be severe in character, it may also never return.
- Polymorphic Lucitis: this is a rarer form of allergy to the sun and produces skin lesions in the form of red patches. It appears with the first rays of the sun but can also occur when there are low levels of sunlight.The rash is only visible 12 hours after exposure and 30 minutes exposure is sufficient to trigger an attack. It disappears as soon as the subject retires to the shade. It reappears after each new exposure and tends to get worse.
It affects women and men in equal proportions.
This type of allergy affects not only the neckline and the arms but also the face and the back of the hands and ears.
- Juvenile spring photodermatosis: this rare form of sun allergy affects boys aged between 5 and 15 years. The rash appears with the first spells of sunshine after cold weather. It is characterized by small spots above the ears, which transform into crusts and disappear within ten days without leaving a mark.
This allergy occurs for a few years, only during the first rays of sunshine, and then disappears of its own volition.
- Solar Urticaria: this is characterized by rashes which appear very quickly after exposure to the sun, then disappear just as quickly once the person returns to the shade. It mainly affects women aged between the ages of20 and 40. The rash covers exposed areas but can also affect those which are covered. It causes raised patches resembling nettle rash. Due to its debilitating consequences, Solar urticaria can make any outside activity impossible, and relapses can occur over a period of several years.
In every case, consult a dermatologist to confirm diagnosis, trust in his expertise and follow his advice.