About Sun Allergy

Overview

Sun allergy, also known as polymorphic light eruption (PMLE), is a skin condition characterized by an allergic reaction to sunlight or other sources of ultraviolet (UV) light. It typically presents as an irritated rash that appears hours to days after exposure to direct sunlight. PMLE is the most common skin condition caused by sunlight and affects approximately 10-20% of the population. Symptoms of PMLE include redness, itching, raised patches of skin, scaling, blisters, and hives. The exact cause of PMLE is unknown, but it is believed to be a delayed hypersensitivity reaction to an antigen expressed after sun exposure. Risk factors for developing PMLE include being female, having lighter skin color, living at a high altitude, and having a family history of the condition. Treatment options for PMLE include home remedies such as applying cool compresses and using over-the-counter anti-itch creams, as well as medical interventions like topical corticosteroids and phototherapy. It's important to consult with a healthcare professional for personalized advice and treatment recommendations.

Causes and Risk Factors

The exact pathophysiologic causes of sun allergy are not fully understood. However, it is believed to be an immune-mediated reaction triggered by exposure to sunlight or artificial sources of ultraviolet (UV) radiation.

Non-modifiable risk factors for sun allergy include:

Age: Sun allergy often develops in women between the ages of 20 and 40.
Altitude: People living at high altitudes above sea level have an increased risk of developing sun allergy.
Lighter skin color: Individuals with lighter skin are more prone to sun allergy compared to those with darker skin.
Gender: Females are 2-3 times more likely to develop sun allergy than males.
Family history: Having a close blood relative with sun allergy increases the risk.

Modifiable risk factors for sun allergy include:

Sun exposure: Prolonged or intense exposure to sunlight, especially during peak hours, can increase the risk of sun allergy.
Sunscreen use: Inadequate or improper use of sunscreen may contribute to the development of sun allergy.
Clothing choices: Wearing clothing that does not provide sufficient protection against UV radiation can increase the risk.

It is important to note that while these factors may increase the likelihood of developing sun allergy, they do not guarantee its occurrence. Taking preventive measures and practicing sun safety can help reduce the risk of sun allergy.

Symptoms

The most common early symptoms of sun allergy, include:

Itchy rash on areas newly exposed to sunlight, such as the chest, forearms, hands, lower legs, and feet.
Redness and inflammation of the affected skin.
Pain or discomfort in the rash area.

As sun allergy becomes more severe, additional symptoms may occur. These can include:

Fever.
Headaches.
General feelings of malaise (unwell).
Blisters.
Hives.

It's important to note that these symptoms can vary from person to person, and not everyone will experience all of them. If you suspect you have sun allergy or are experiencing these symptoms after sun exposure, it is recommended to consult with a healthcare professional for a proper diagnosis and appropriate treatment.

Diagnosis

Sun allergy is typically diagnosed based on its symptoms and the appearance of the rash. However, there are certain examinations, tests, and procedures that can be performed to confirm the diagnosis. These include:

Physical Examination: A thorough examination of the affected areas by a healthcare professional can help assess the extent and severity of the rash.
Medical History and Symptom Assessment: Evaluating the specific symptoms experienced, such as itching, redness, blisters, or hives, can provide insight into the severity of sun allergy.
Skin Biopsy: In some cases, a small piece of skin may be removed and examined in a laboratory to confirm the diagnosis of sun allergy.
Blood Tests: Blood tests may be conducted to rule out other conditions that may cause similar symptoms.
Photo-testing: This procedure involves exposing a small area of your skin to measured amounts of ultraviolet light. If your skin symptoms appear after this exposure, it confirms that your skin eruption is sun-related.

It's important to consult with a healthcare professional for an accurate diagnosis and appropriate management of sun allergy. They will guide you through the necessary examinations, tests, and procedures based on your individual situation.

Treatment Options

The goals of treatment for sun allergy, are to decrease discomfort and protect the skin from further damage. Here are the recommended treatments and how they work to achieve these goals:

Sun Protection:

Using SPF 50 sunscreen: Applying sunscreen with a high sun protection factor (SPF) helps to block harmful UV rays.
Wearing protective clothing: Wearing long-sleeve shirts, pants, wide-brimmed hats, and wraparound sunglasses can shield the skin from direct sun exposure.
Avoiding sun exposure between 10 a.m. and 4 p.m.: Staying in the shade during the peak hours of sunlight reduces the risk of developing a sun rash.

Gradual Skin “Hardening”:

This treatment involves carefully exposing the skin to sunlight or using phototherapy under the guidance of a dermatologist.
It helps build up tolerance to UV light, reducing the severity of sun poisoning eruptions over time.

Medications:

Oral steroids: In severe cases, oral corticosteroids may be prescribed for short-term use.
Hydroxychloroquine: This medication can help reduce inflammation and suppress the immune response.

Supplements:

Polypodium leucotomos extract: An oral supplement that may provide photoprotective effects.
Lycopene, nicotinamide, beta-carotene, astaxanthin, canthaxanthin: These supplements have been suggested to potentially help reduce sun poisoning symptoms, but their efficacy is not well-established.

It's important to remember that specific medication dosing may vary depending on individual circumstances. Always consult with your healthcare professional before starting any new medications or treatments.