Photosensitivity – Symptoms, Causes, And Treatment

Photosensitivity or sun sensitivity refers to the skin reaction occurring due to ultraviolet (UV) exposure. You suffer from such reactions due to extreme sensitivity to UV rays from the sun and/or other sources of light. When you expose your skin to sunlight for a long time, you develop sunburn or sun rash poisoning. Excessive exposure to harmful sun radiation can result in irreversible skin damage and skin cancer. But, people who suffer from sun sensitivity can develop rashes or burns with limited exposure to sunlight. The condition, also referred to as sun allergy is a serious problem that you need to learn more. With comprehensive information, you can take the necessary steps to prevent any irreversible complications.

Types Of Photosensitivity

Types Of Photosensitivity You can suffer from different types of photosensitivity problems. Due to the underlying condition triggering the problem, you can see the itchy eruption, areas of redness, and inflammation. It usually occurs in areas exposed to sunlight.

Photosensitivity Due To Diseases

In some cases, you can inherit the condition or suffer from it due to suffering from diseases like porphyrias and systemic lupus erythematosus.

Chemical Photosensitivity

As the name suggests, chemicals you apply or swallow can trigger sun-induced reactions on your skin. You can classify it into two types.


These reactions occur when you introduce a new chemical in the body and it interacts with the ultraviolet rays from the sun. Due to the condition, you suffer from severe sunburn and it develops within 24 hours of your exposure to the sun. You also suffer from inflammation and redness in your skin. You can see brown or blue-gray discoloration in areas your body gets exposed to sunlight. People usually develop it when you take certain drugs. So, medications like tetracycline, doxycycline, or diuretics can result in the condition. Applying chemical compounds on your skin like coal tar and perfume can also cause sun allergy.


Some people suffer from reactions after they come in contact with some plants containing furocoumarins. These are found in parsley, celery, and limes. So, coming in contact with such plants makes your skin sensitive to the effects of UV light. This reaction is known as phytophotodermatitis. You suffer from phototoxic reactions in the areas exposed to sunlight. These reactions develop within hours of sun exposure.


You develop a photoallergic reaction as a side effect of some medications. It is also triggered as a result of your skin coming in contact with beauty products or sunscreen. These types of reactions take a few days to develop after sun exposure. The condition can trigger scaling, redness, itching, and at times blisters as well as spots, resembling hives. The reaction occurs when you are exposed to both chemicals (found in sunscreens, aftershave lotions, and sulfonamides) and sunlight. It is because the sunlight makes the substance capable of triggering sun allergy. In photoallergy, you can also suffer from reactions in areas not exposed to sunlight. You develop the reaction 24 to 72 hours after exposing your skin to sunlight.

Symptoms Of Photosensitivity

Symptoms Of Photosensitivity

How can you understand that you have suffered from photosensitivity? By observing the changes in your skin exposed to sunlight, it is possible to uncover the problem. Depending on the amount of sun exposure, your symptom can vary from mild to severe. The severity of the problem depends on the person suffering from it. In some people even very little sun exposure can trigger a reaction. The skin problems associated with the condition are:

Mild Symptoms

  • The appearance of exaggerated sunburn or skin rash
  • Presence of itching/no itching at the rash site

Severe Symptoms

Causes Of Photosensitivity

So, what are the exact reasons for suffering from sun allergy? When you go out in the hot sun, the exposed parts of your skin can receive UV light. When it is absorbed by your skin, it triggers an immune reaction. The immune system immediately releases inflammatory mediators as a response to blood vessel dilation happening in your skin. This process can result in the development of rash as well as other symptoms. Depending on the underlying cause, you can classify into the following types:

Exogenous Photodermatoses

It is the type of sun allergy caused when you suffer from a phototoxic or photoallergic reaction due to an external photosensitizer. It includes the following:

  • Drug-induced photosensitivity
  • Coming in contact with phototoxic chemicals in plants like psoralens
  • Renal insufficiency and taking of certain drugs triggers pseudoporphyria

Primary Photodermatoses

It is caused when you are exposed to the ultraviolet component of the sun. It can result in abnormal skin reactions like solar urticaria or other problems. Due to the condition, you develop certain symptoms after sun exposure. People suffer from issues like juvenile spring eruption, actinic prurigo, actinic folliculitis, chronic actinic/photosensitivity dermatitis, hydroa vacciniforme (it is associated with Epstein Barr virus). But, the common ones are solar urticaria and polymorphic light eruption.

Solar Urticaria

Solar Urticaria

In this type of sun allergy, you develop hives a few minutes after sun exposure. So, due to your skin coming in contact with the UV rays, you develop large, red, and itchy welts or bumps. You can experience the hives for a few minutes or hours. If you are prone to developing solar urticaria, then the condition can exist for a long time. In some cases, the problem affects a person indefinitely. People who have large affected areas of sun allergy can experience the following symptoms:

  • Nausea
  • Headaches
  • Wheezing
  • Dizziness
  • Weakness

Polymorphic Light Eruption

Polymorphic Light Eruption

It is the most common reaction developing in people due to exposure to sunlight. This occurs when your skin comes in contact with UVA light. This problem is common among women as well as people who are from northern climates, which makes regular sun exposure impossible. Due to the eruptions, you can see multiple red bumps developing on your skin. The eruptions look irregular and red. The may have plaques (the raised areas) and in rare cases, form blisters on the sun-exposed part of your skin. The new patches develop many hours or days later, after your sun exposure. You can see the eruptions going away after several days or weeks. In people who develop the condition, their skin becomes less sensitive to sunlight as they continue to go out. So, the effects of sunlight on skin ease. This process is referred to as hardening.

Genetic Photodermatoses

When you suffer from genetic disorders like Bloom syndrome or xerodermpigmentosum, you can suffer from sun allergy.

Metabolic Photodermatoses

As the name suggests, you experience sun sensitivity or allergy due to some underlying metabolic disorders. So, conditions like porphyria can lead to the condition.

 Photo-Exacerbated Dermatoses

Suffering from autoimmune diseases can result in photosensitivity. So, people who suffer from the following issues can develop sun allergy:


If you are suffering from psoriasis, it means your skin cells tend to multiply ten times faster than normal. It can cause the development of bumpy red patches. These red patches are covered with white scales. You can develop the condition anywhere on the body. But, it mostly develops on your lower back, knees, elbows, and scalp. Sun exposure can result in the worsening of sun allergy symptoms.

Systematic Lupus Erythematous

When you suffer from lupus, which is a connective tissue disease, you develop different problems on your skin. So, you can see lumps, red patches, and purple spots that develop on the sunlight exposed areas of the skin.

Actinic Prurigo

When you suffer from the condition, you will develop red bumps after you go out in sunlight. Then, these red bumps turn into scaly patches. People suffering from this disorder can experience the symptoms year around. So, the rashes not just develops in the summer season, but also in winter when you are less likely to experience sun exposure.

 Acne Rosacea

Acne rosacea is the skin problem triggering redness as well as the development of pus-filled bumps. These small yet red bumps develop mostly on the face. Certain conditions can trigger the problem like sun exposure. Sue to over sun exposure, the blood vessels in your skin dilate.

Atopic Dermatitis

Atopic dermatitis, commonly known as eczema causes inflammation of your skin. It is the sin condition that causes itching and redness of your skin. It is a long-lasting problem, flaring up occasionally due to triggers.

See Doctor Immediately For Photosensitivity

While you need to see a dermatologist when you develop a rash, you need immediate medical when you experience the following:

  • An itchy rash that does not go away by using over-the-counter treatments
  • You develop a rash on large areas of the body, including areas not exposed to sunlight (not covered by clothes)
  • A rash that involves large areas of your body, including parts that are covered by clothing
  • See abnormal bleeding under your skin in the areas exposed to sunlight
  • A persistent rash covering your face (It is specifically serious when you are a woman or have an American-Indian heritage)
  • Develop hives along with swelling around the lips or eye
  • Fainting spells
  • Trouble breathing
  • Difficulty swallowing

The above-mentioned symptoms indicate something serious. In most cases, the signs can suggest a life-threatening allergic reaction, which can prove fatal. So, get immediate medical assistance as early as possible.

Diagnosing Photosensitivity

When you observe skin rashes, you may think it is sun rash. Since you have no specific test to determine the photosensitivity reactions, your dermatologist can adopt several methods to come to a conclusive diagnosis. Here are the methods used to detect the issue conclusively:

Physical Evaluation

When you see the symptoms related to the condition, see a dermatologist. It is essential to determine the exact cause of the skin problem. So, your doctor looks closely at the areas with the rash. If you develop a rash in the areas exposed to sunlight, then your doctor suspects sun allergy. During the evaluation, your doctor checks for your medical history along with the skin symptoms. If you take medications for any underlying disease, then you need to inform your doctor about it. It is also essential to inform your doctor regarding the substances you apply to your skin (like any cosmetics or drugs) as it can help your doctor pinpoint the exact cause of the reaction. Some underlying health conditions can make you susceptible to skin reactions (for example systemic lupus erythematosus).

Blood Tests

If your doctor suspects the presence of any underlying condition causing sun allergy, then you need to undergo blood tests. A complete blood count reveals the presence of porphyrins in your blood along with antinuclear antibodies. So, using the test, your doctor can rule out health conditions like porphyria as well as systemic lupus erythematosus.


Also known as the skin patch and reaction reproduction test, your doctors order it to get the exact cause of the problem. It is suggested when a rash occurs on the area of your skin exposed to sunlight. It is essential when the diagnosis of the problem is not clear. So, the test involves exposure to UV light with both UV-A and UV-B. It is important to rule out the presence of any drugs triggering the skin reaction before the test. The small area of your affected skin is treated by gradually increasing the dose of light. With the test, it becomes possible to detect the exact type of reaction triggering the problem.

Photopatch Test

A substance or material that is considered to be causing sun sensitivity is pasted on the skin and exposed to UV light. If a rash develops within 24 to 48 hours of the exposure, then the test is considered positive for sun sensitivity.

Photosensitivity Treatment Options

If you have a sun allergy, then you need to get treatment to avoid the problem from triggering complications. But, the first step is to diagnose the problem. So, consult your dermatologist to detect the exact problem. You need to follow the guidelines suggested in the preventive section to avoid the worsening of the problem. Following the guidelines will reduce sun exposure as well as prevent the problem from escalating. Further treatment depends on the specific type of sun allergy.

Treatment For PMLE (Polymorphic Light Eruption)

Depending on the severity of the specific type of sun allergy, your dermatologist suggests a treatment option. The milder cases of the problem are easy to manage at home. While severe problem needs advanced treatment.

Treatment For Mild PMLE Photosensitivity

Mild symptoms are easy to deal with at home. So, after the diagnosis from the dermatologist, you can follow the steps suggested below:

Cool Compress

Apply the cool compress on the affected area to reduce the discomfort and skin irritation. Cool compresses like damp washcloth or sprays of cool water on the areas with itching, rashes, and other skin problems can offer you relief.

Use Over-The-Counter Antihistamine

You can also try using a nonprescription antihistamine that you can take orally (by mouth). So, you can take medications like chlorpheniramine or diphenhydramine (sold under different brand names) to relieve the distressing symptoms like itching. You can also apply a cream containing cortisone on affected areas to get relief from skin problems caused due to photosensitivity.

Treatment For Severe PMLE

For severe cases, you need prescription treatments. So, your dermatologist can suggest the following options:

Prescription Strength Medications

When the over-the-counter medications fail to offer you relief, then the doctor suggests prescription-strength oral antihistamines to reduce the distress. You can also apply prescription-strength corticosteroid cream for better results.

Phototherapy For Photosensitivity

When the above-mentioned options fail to offer effective results, your doctor prescribes phototherapy. It makes your skin harden by gradual exposure to ultraviolet light doses. It is increased steadily with the sessions. So, you get five ultraviolet light exposure each week over three weeks.

Combination Therapy

It is combining different treatment options to offer you relief when phototherapy fails. So, your doctor uses a combination of techniques like using psoralen (a light-sensitive drug capable of absorbing ultraviolet light) along with PUVA ultraviolet light. The doctors prescribe beta-carotene or antimalarial drugs for oral consumption. A combination of these therapies can offer the desired results.

Treatment For Actinic prurigo (Hereditary PMLE)

A cure is not available for this type of photosensitivity. But, the dermatologist suggests preventing the condition by avoiding sun exposure. So, you need to limit going out during peak hours. People who suffer from the condition need to understand that their condition can worsen during the sunniest months of the year. So, you need to adhere to all the sun protection strategies suggested by the doctor to reduce or avoid the outbreaks. If you suffer from the condition, then you need to use the following medications to relieve the symptoms of actinic prurigo. The suggested treatment includes:

  • Using emollients to reduce itching due to the rashes.
  • Use topical corticosteroids.
  • For relieving inflammation take anti-malarial medications like hydroxychloroquine as they have anti-inflammatory properties.

Thalidomide is used with caution as it can cause certain side-effects. So, it is gradually reduced when you see improvement. It is not advised for women of childbearing age as it can result in birth deformity.

Photoallergic Eruption Treatment

The treatment aims to identify the medicine or skincare product triggering allergic reaction. You need to eliminate it to avoid the problem. The doctor also prescribes corticosteroid cream to heal other skin symptoms.

Solar Urticaria Treatment

For treating mild hives triggered due to solar urticarial, the doctors suggest OTC oral antihistamine or an anti-itch cream containing cortisone. It relieves itching. For severe cases, the doctor suggests prescription-strength corticosteroid cream or antihistamine. For extreme cases, you need to undergo phototherapy, take antimalarial drugs or PUVA.

Preventing Photosensitivity

It is possible to prevent sun allergy by taking ample precautions. For avoiding any bad consequences, you need to protect your skin from the harsh effects of sunlight. So, you can follow the suggestions provided below:

Apply Sunscreen

Before you make a trip outdoors, you need to apply sunscreen. Opt for a product with SPF (Sun Protection Factor) of at least 30 or above. It offers your skin protection against the harmful ultraviolet A and ultraviolet B radiation. Also, never miss your lips. So, you need to use a sunblock formulated especially to avoid harsh effects of sun on your lips. Choose a sunblock with SPF 30 or more for better protection.

Limit Your Time Outside

You need to limit the time you spend outside. So, you need to prevent going outside in the sun during the peak hours like 10 a.m. to 4 p.m. By avoiding the sun during peak hours, you limit the solar radiation at its strongest.

Use Necessary Accessories

While going out, use hats wide brim and sunglasses with UV (ultraviolet light) protection. To keep your skin safe from photosensitivity, you need to wear long pants that cover your legs and shirt with long sleeves to offer protection to your arms from harmful sun radiation.

Check The Label Of Skin Products/Medicines

Some skin care products and medications can trigger photoallergic eruption. Therefore, check the label and consult with your dermatologist. If you are taking antibiotics or other prescription medication, ask your doctor for instructions. Some people need to spend a lot of time outside as a part of their job. So, getting a doctor’s advice about taking special precautions while using the medication to avoid sun exposure will help you prevent any serious skin issues.


The prognosis of photosensitivity depends on the type of problem you suffer. But, if you follow all the preventive measures, including using sunscreen along with protective clothing while you go outside offer a good outlook. People suffering from Actinic prurigo and PMLE have a better outlook after five to seven after the diagnosis. While photoallergic eruption is easy to overcome when you avoid specific chemicals triggering the allergic reaction. But, sun allergy, like solar urticaria is the most problematic one as it causes long-term problems. But, in some people, this form of sun allergy eventually subsides. So, to keep yourself safe from the wrath of sunlight, you need to take necessary actions and precautionary measures.

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