Sun allergy isn’t a specific diagnosis. Instead, it’s an umbrella term for a variety of skin reactions that occur following sun exposure. According to Dr. Rehan Karim of U.S. Dermatology Partners North Dallas, “Sun allergy, a term that describes several different types of skin sensitivity related to UV exposure, is more common than most people think. These reactions go beyond a typical sunburn and may include intense itching, hives, bumps, blisters, or a rash that develops shortly after sun exposure. If you notice a consistent pattern of these symptoms after spending time outdoors, it’s important to have your skin evaluated by a dermatologist to determine the underlying cause and recommend appropriate treatment.” In this blog, Dr. Karim talks about sun rash and other allergy responses to UV exposure and how prevention, diagnosis, and dermatologic treatment reduces symptoms and improves skin health.
What Is a Sun Allergy?
Unlike a sunburn, which develops when UV radiation damages the skin, a sun allergy occurs when the body’s immune system reacts abnormally to sunlight. The term sun allergy describes several different conditions that can trigger symptoms such as itching, hives, bumps, blisters, or a rash after sun exposure. Genetics, certain medications, underlying medical conditions, and other factors may all increase the likelihood of developing these reactions.
Common Types of Sun Allergies
According to Dr. Karim, “Since the symptoms of sun allergies are usually limited to negative skin responses, it can be difficult to understand how being allergic to sunlight goes beyond the skin. While there may be symptoms similar to sunburn, patients may experience more advanced allergic responses like hives and rashes.” In addition to differentiating sun allergies from sunburns, Dr. Karim emphasizes the importance of understanding the different types of sun allergies, including:
- Polymorphous Light Eruption (PMLE) – this is the most common type of sun allergy, and it’s what most people are referring to when they say sun rash. PMLE almost always accompanies the first sun exposure of the spring or summer, and it may recur throughout warmer seasons. It causes itchy red bumps, small blisters, or patches of thickened skin on sun-exposed parts of the body.
- Solar urticaria – this condition is a rarer and more severe form of sun allergy than PMLE. It causes raised hives accompanied by intense itch that can interfere with sleep and daily activities. These symptoms usually develop very quickly after direct sun exposure.
- Photoallergic reactions – this type of sun allergy is linked to the interaction of UV light with medications like antibiotics and anti-inflammatories as well as certain fragrances or skincare products. The good news is that photoallergic reactions improve once the medication, fragrance, or skincare product is removed from daily routines. Always talk to a medical professional before discontinuing medication.
Who Is Most Likely to Develop a Sun Allergy?
Anyone can develop sun allergies, but some patients are at higher risk including those:
- With fair skin.
- Who have a family history of sun allergy.
- Diagnosed with an autoimmune disease.
- Taking certain medications.
- Living in low-light areas.
- Who previously had photosensitive reactions.
- Who are female (specifically, PMLE is more common in women).
What Causes Sun Allergies?
The exact causes of sun allergies will vary based on the underlying causes. In general terms, sun allergies occur when the body’s immune system responds too aggressively to sun damage, but some underlying causes and risk factors for sun hives and allergic responses include:
- Overactive or highly reactive immune system.
- Genetic predisposition.
- Environmental factors (like minimal sunlight in winter months).
- Medications (like antibiotics and anti-inflammatories).
- Chemicals (from fragrances, cosmetics, etc.) reacting negatively with sunlight.
How Dermatologists Diagnose Sun Allergies
To diagnose sun allergies, Dr. Karim says, “It all starts with the patient. When someone notices a pattern of photosensitivity or allergic response following sun exposure, they should document it and reach out to their dermatologist to schedule a diagnostic evaluation.” During a diagnostic consultation, dermatologists will:
- Review medical history – this includes discussing the timing of symptoms, patterns of recurrence, and other sun allergy characteristics while ruling out potential skin health concerns that may be causing rashes.
- Medication review – some medicines contain known photosensitizing drugs. If you’re taking one or more of these medications, that may be the cause of sun allergy.
- Physical examination – it’s best to visit during an active sun allergy flareup. This gives your dermatologist an opportunity to carefully examine impacted skin and gather additional information as needed.
- Phototesting – this involves the use of controlled UV rays to confirm UV radiation is the allergy trigger and document the severity of symptoms.
- Skin biopsy – in some cases, skin biopsy may be necessary to confirm diagnosis or rule out conditions with similar symptoms.
Sun Allergy Treatment Options
Following diagnosis, there are a variety sun allergy treatment options your dermatologist may recommend depending on the type of sun allergy and severity of symptoms. Treatment often includes a combination of medications to relieve symptoms, therapies to reduce skin sensitivity, and sun protection strategies to help prevent future flare-ups. Some of the most common treatment options include:
- Topical corticosteroids – These over-the-counter or prescription creams can help reduce inflammation, redness, and itching during a sun allergy flare.
- Oral antihistamines – These medications may help relieve hives and itching. Depending on your symptoms, your dermatologist may recommend an over-the-counter or prescription-strength antihistamine.
- Light hardening therapy (phototherapy) – This treatment gradually exposes the skin to controlled amounts of UV light under dermatologist supervision. Over time, it may help reduce sensitivity to sunlight and decrease the frequency or severity of recurrent flare-ups.
- Sun protection – Protecting your skin from UV exposure is an essential part of managing sun allergies.
How to Prevent Future Sun Allergy Flares
Preventing sun allergy flareups in the most basic terms involves reducing sun exposure. Some practical prevention tips include:
- Apply a broad-spectrum sunscreen with SPF 30+ daily.
- Reapply sunscreen every two hours.
- Minimize time outside or seek shade during peak hours between 10 am and 4 pm.
- Wear UPF sun-protective clothing.
- Start with small periods of sun exposure in spring and summer and increase gradually as tolerated.
- Identify and avoid symptom triggers.
- Talk to your medical provider if you’re concerned side effects may be linked to worsening sun allergy symptoms.
When Should You See a Dermatologist?
Many patients put off visiting a dermatologist believing their symptoms will get better on their own or that it’s nothing serious, but it’s important to schedule a dermatology consultation if you experience:
- Chronic rash or hives following sun exposure.
- Symptom severity interferes with day-to-day activities.
- Itching, blistering, swelling, or fever occurs.
- No improvement with over-the-counter treatments.
- Medication reactions that contribute to sun allergies.
Sun Allergies Require Unique Intervention
Finally, Dr. Karim says, “Sensitive skin and sunburn are common skin conditions that can often be addressed with at-home care or prevention steps. Sun allergies of any kind require dermatologist diagnosis and treatment planning. Without proper diagnosis, patients may seek the wrong treatments, which could worsen symptoms. Working with a dermatologist, you’ll receive the right treatment and education about how to prevent these reactions.”
Learn More at a Dermatology Consultation
Recurring rashes, hives, or irritation following sun exposure are not normal, and they should not be ignored. Instead, schedule an appointment with a dermatologist who can help you better understand these adverse reactions and how to prevent and treat them. Getting started working with U.S. Dermatology Partners is quick and easy. Just take a few moments to complete our online scheduling request form. Once we hear from you, a local dermatology team member will be in touch to finalize the details of your upcoming visit.
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