How to avoid UV allergy in the scorching summer? (Photo)

       What exactly is ultraviolet (UV) light?

Ultraviolet light refers to the collective radiation in the electromagnetic spectrum with wavelengths ranging from 10nm to 400nm, which is invisible to the human eye. In 1801, German physicist Ritter discovered that a section beyond the violet end of the sunlight spectrum could expose photographic plates containing silver bromide, thereby discovering the existence of ultraviolet light.

Based on intensity, UV light can be divided into three types: UVA, or long-wave ultraviolet, is the strongest type of UV and is not affected by season, weather, or time of day. It can penetrate glass, clothing, and everyday protective gear to cause sunburn and premature skin aging; UVB, or medium-wave ultraviolet, can damage exposed skin, leading to darkening, redness, swelling, and even spots; UVC, or short-wave ultraviolet, causes almost no harm to the skin. UV intensity is strongest right after summer rain clears; between 10 a.m. and 2 p.m. daily is when UV is at its peak.

What is “UV allergy”?

UV allergy is an abnormal hypersensitive reaction caused by sunlight acting on the human body; photoallergic reactions are immune responses where even small amounts of photosensitive substances in the body can react upon UV exposure. This manifests as rashes such as erythema, papules, wheals, or blisters on exposed areas like the face, neck, forearms, and backs of hands. These skin lesions worsen significantly after sun exposure, with itching intensifying. The rashes often recur, and over time may lead to lichenification and increased pigmentation. Symptoms are especially severe in spring, summer, and autumn; this condition is also called solar dermatitis.

After intense sun exposure in midsummer, exposed skin areas such as the neck, face, arms, and shoulders may develop erythema, blisters, and a burning, intolerable itch. After several days, the erythema and swelling subside, followed by peeling and temporary pigmentation. This process is an acute injury response of the skin under strong sunlight, known as sunburn. Repeated sunburns can also make the skin sensitive to light, leading to photosensitive reactions (solar dermatitis) upon subsequent sun exposure.

Traditional Chinese medicine refers to this condition as “sunburn sores,” where yang heat toxins invade the body surface, accumulate in the skin, scorch the skin, and injure the flesh. If the toxic heat combines with summer dampness or internal dampness, soaking into the skin can cause swelling and blisters, which may rupture, ulcerate, and exude fluid.

What factors lead to UV allergy?

Foods that can trigger UV allergy include celery, lettuce, rape, spinach, amaranth, bok choy, alfalfa, pigweed, mustard greens, kalimeris, purslane, safflower, figs, sheep’s sorrel root, lemon, white radish, cilantro, and leeks—all of which contain photosensitive substances and are considered photosensitive plants. Overconsumption of these plants followed by sun exposure can result in UV allergy symptoms.

What are the symptoms of UV allergy?

Symptoms of UV allergy include itching in areas exposed to sunlight. The longer the sun exposure, the more severe the allergic reaction. Skin itching may persist for 24 to 48 hours or even longer.

Ultraviolet rays in sunlight may cause cataracts. Since the damage to the eyes from sunlight is not easily noticeable in the short to medium term, its potential threat should not be ignored.

When the skin is exposed to UV light, rashes may appear on exposed areas such as the face, neck, and backs of hands. Depending on the severity of the skin reaction, it is classified as first-degree or second-degree UV allergy.

First-degree UV allergy presents as diffuse erythema on the skin after sun exposure.

Second-degree UV allergy involves skin swelling followed by blistering or even large blisters with taut walls and pale yellow fluid. Sensations may include burning or itching. Once the blisters rupture, they form erosive surfaces that soon dry and scab, leaving behind pigmentation. Severe UV allergy may be accompanied by systemic symptoms such as fever, headache, palpitations, fatigue, nausea, and vomiting.

Netizens complain: What to do about UV allergy?

The occurrence of UV allergy symptoms is related to individual constitution and skin tone—those who are weaker, have fairer or more sensitive skin tend to have more severe symptoms. Additionally, it is related to the duration and extent of sun exposure, with higher incidence in high-altitude areas. Taking medications such as sulfonamides, chlorpromazine, or griseofulvin, or eating certain vegetables or wild greens like amaranth, pigweed, alfalfa, or locust flowers before sun exposure can also trigger UV allergy symptoms. UV allergy sufferers typically experience regular annual outbreaks, with the highest incidence among young and middle-aged women. Symptoms begin after sun exposure in spring and summer and gradually improve in autumn and winter. Over time, the affected skin areas may thicken, become rough, darken, and develop unsightly pigmentation, causing significant damage to healthy, beautiful skin.

How to avoid UV allergy in summer

1. Avoid cosmetics containing high levels of photosensitive substances, such as fragrances.

2. Prevent prolonged sun exposure. During spring outings, use wide-brimmed hats or umbrellas for shade.

3. Those with a history of seasonal dermatitis may apply sunscreen appropriately to protect the skin from various UV and visible light wavelengths.

4. Eat more foods rich in vitamin A as well as fresh vegetables and fruits to maintain normal skin function. Try to eat less or avoid photosensitive foods that may induce springtime dermatitis, such as rape, spinach, lettuce, and figs.

5. When washing your face, avoid using hot water, alkaline soap, or rough towels.

6. Do facial beauty exercises daily. The method is as follows: clasp your fingers together, rub your palms until slightly warm, then gently massage the forehead, cheek, nose, and ear areas for 3–5 minutes to promote facial blood circulation, keep the skin smooth, and help prevent UV allergy.

UV allergy

Doctor: “First, be sure to apply a cold compress—don’t use hot water. Take some oral antihistamines. Don’t use topical ointments without advice; it’s best to see a doctor.”

Doctors recommend that patients who are sensitive to light can train their skin to build up tolerance to ultraviolet rays before summer arrives, in order to prevent sun allergy in advance.

“UV allergies are generally caused by long-wave or medium-wave UV rays. You can start with short periods of exposure to these rays, gradually increasing the time to help the skin adapt.”

At the same time, using sunscreen scientifically is also an effective way to prevent UV allergy. Apply sunscreen about half an hour before going out, and reapply after some time. In addition to external protection, regularly eating foods such as tomatoes, lemons, and nuts can help protect against UV rays and whiten the skin. However, photosensitive vegetables like white radish, celery, and cilantro can easily lead to skin pigmentation, so it's best to eat less of them during seasons with strong sunlight. Moreover, carrying an umbrella, wearing a hat, or putting on long-sleeved clothes are also good ways to block UV rays. Wide-brimmed sun hats and dark-colored silver-coated umbrellas offer better protection.

What medicine should I take for UV allergy?

Experts believe that Western medicine typically treats UV allergy with anti-allergy medications to relieve symptoms. Traditional Chinese medicine, on the other hand, focuses on syndrome differentiation and treatment, addressing the condition based on clearing heat and toxins, removing dampness, relieving itching, and categorizing the type of allergy.

In emergencies, you can take antihistamines such as Claritin (one tablet per day), along with vitamin C tablets, calcium gluconate tablets, compound vitamin B tablets, and OPC grape seed extract.

UV allergy is an immune response and requires long-term care. For those with severe skin symptoms, a combination of Chinese and Western medicine treatments may be used.