Whenever she went outdoors, especially in strong sunlight, tiny red spots would appear on Huong's face, neck, arms, and chest, accompanied by itching and a stinging sensation. Taking antihistamines provided relief for a few days before symptoms recurred. Recently, after just 15 minutes in the sun, her exposed skin developed extensive red, swollen, and intensely itchy patches.

Dr. Nguyen Thi Viet Ha, a dermatologist at Tam Anh Cau Giay General Clinic, observed lesions concentrated on areas directly exposed to sunlight. After reviewing her medical history and conducting necessary tests, the doctor diagnosed Huong with a sun allergy.

Dr. Ha examines Huong. *Photo: Tam Anh Cau Giay General Clinic*

Dr. Ha explained that sun allergy is an abnormal immune system reaction that occurs when skin is exposed to ultraviolet (UV) rays from sunlight. This condition can affect people of all ages but is more common in young women, individuals with sensitive skin, or those with a history of allergies. Symptoms typically appear minutes to several hours after sun exposure and include redness, itching, rash, burning sensations, swelling, or small blisters. Lesions primarily concentrate on the face, neck, shoulders, arms, and chest.

Many people often confuse sun allergy with common sunburn. However, sunburn is direct damage caused by UV rays, whereas sun allergy involves an immune system response. Several factors increase the risk of developing this condition, including an allergic predisposition, the use of certain medications, cosmetics, perfumes, or skincare products containing photosensitive ingredients. Individuals with autoimmune diseases also face a higher risk.

Dr. Ha noted that self-medicating with antihistamines or inappropriate topical creams can mask symptoms, making diagnosis difficult. In some cases, the misuse of corticosteroid-containing drugs can lead to skin thinning, dilated blood vessels, hyperpigmentation, and various other complications.

After receiving medication and appropriate skin care, Huong's condition significantly improved. The doctor provided her with guidance on long-term skin protection to minimize the risk of recurrence.

Huong needs to limit direct sun exposure between 10:00 AM and 4:00 PM, wear sun-protective clothing, wide-brimmed hats, and eye protection. She should use sunscreen with an appropriate SPF rating daily, even on cloudy days. Additionally, she should choose skincare products suitable for her skin type and avoid overusing cosmetics or unverified products.

If recurrent redness, itching, or rash appears after sun exposure, patients should seek medical attention for examination, diagnosis, and timely treatment to prevent prolonged damage that could affect their quality of life.

Thanh Ba