What is Photodermatitis?

Photodermatitis is a condition that refers to the inflammation of the skin and is also known as sun allergy, sun burn or sun poisoning. The primary factor that triggers this problem is the Sun itself, i.e. the allergens that react against the skin are only able to manifest themselves when the skin is exposed to the sunlight.

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Activation of the allergen in the presence of sunlight, particularly the ultraviolet rays of the sun results in scaly patches, skin rashes and blisters. Moreover, people cannot shelter themselves completely from the sun which makes it difficult to curb the effects of photodermatitis as the condition worsens due to repeated exposure to sunlight.

Types of Photodermatitis

  • Genetic or Metabolic Photodermatoses: In this type, the phoyosensitizer is formed and deposited on the skin. Examples include variegate porphyria, pellagra and xeroderma pigmentosum. These conditions are commonly prevalent in the individual’s family, which indicates towards a genetically induced problem.
  • Idiopathic Photodermatoses: The photosensitization reaction remains unknown for this type of dermatitis. They include actini prurigo, polymorphic light eruptions, chronic actini dermatitis and solar urticaria.
  • Systematic and Cutaneous diseases: Conditions such as acne, eczema, herpes simplex, systematic lupus erythematosus and roseaca are caused due to the exposure to the ultra violet rays of the sun.
  • Exogenous chemical or Drug Reactions: Certain cases of photodermatitis may occur if the photosensitizers are topically applied on the skin or ingested, causing phototoxic and photo allergic reactions.

Causes of Photodermatitis

  • Immunological Diseases: Conditions such as solar urticarial, pellagra and systemic lupus erythematosus are capable of causing and worsening photodermatitis. Exposure to ultraviolet rays of the sun is known to aggravate the condition even further.
  • Phototoxic: Sometimes the use of certain medications like non steroidal anti inflammatory drugs, antibiotics, antifungal, diuretics, anti anxiety medications, anti psychotic drugs, anti malarial drugs, chemotherapeutic agents, etc. can have a direct toxic effect. These medicines cause an allergic reaction when they are stimulated in the presence of sunlight. Further, the skin becomes even more sensitive to the ultra violet rays. It takes time ranging from a few minutes to hours to trigger off the reaction.
  • Polymorphous Light Eruptions (PLE): Red and itchy skin rashes may appear in the form of vesicles or hives due to increased exposure to sunlight. This is prevalent especially during the summers when people are in contact with the ultra violet rays for a longer period of time and the rays also tend to be stronger, Image Source:
  • Photoallergic: Substances present in food or items like medication, perfumes, industrial cleaners, sunscreens, drugs, etc. can cause photodermatitis. The above mentioned things may contain allergens that have an allergic reaction when they are ingested or applied in the presence of sunlight. Some individuals are diagnosed with photosensitivity which refers to the skin reacting to sunlight and the subsequent outbreak of rashes, blisters, etc.

Symptoms of Photodermatitis

  • Chronic thickening of skin
  • Skin becomes scarred
  • Itchy, scaly blisters
  • Raised skin
  • Hyper pigmentation and discoloration of skin
  • Outbreaks in areas of the skin that are exposed to sunlight
  • Pain in the affected area
  • Erythema and swelling of the affected area
  • Chills
  • Fever
  • Nausea
  • Headache
  • Lesions appear like eczema
  • Burning sensation on the skin
  • Blotches on the skin that remain for a prolonged period
  • Small fluid filled blisters may appear
  • Fatigue

Prevention of Photodermatitis

  • Avoid going out in the scorching sun
  • Cover your skin by wearing long sleeves, full trousers and using a scarf to cover your face
  • Avoid using tanning devices
  • Apply sunscreen before going out in the sun
  • Do not expose yourself to the sun for a period of time
  • Check and avoid any items such as medications, cosmetics or food items that cause or promote sensitivity
  • Use sunscreens that are PBA free with SPF ranging between 30 – 50

Risks of Photodermatitis

  • People who suffer from lupus, polymorphous light eruptions or porphyria are at a higher risk of having photodermatitis
  • Risk of developing photodermatitis increases with an increase in the time (30 minutes – several hours) spent while exposed to the ultra violet rays of the sun
  • Irrespective of their racial or ethnic background, people with fair or light skin, blonde or red hair and blue or green eyes are highly prone to suffer from a condition of photodermatitis

Complications of Photodermatitis

  • Skin ages faster
  • Dark patches or hyper pigmentation may appear on the skin even after the inflammation ends
  • Photosensitivity may lead to chronic photodermatitis
  • Melanoma or basal cell or squamous cell skin cancer may also develop

Diagnosis of Photodermatitis

  • Physical examination of the individual
  • Examination of the allergies that have manifested themselves on the individual’s body
  • Checking the medical background to understand the possible causes and the allergens responsible
  • Blood test may be conducted to rule out other causes of such rashes such as HIV or herpes

Treatment of Photodermatitis

  • Medications: Doctors migh prescribe any of the following medicines:
    – Glucocorticoids that target skin eruptions
    – Nicotinamide or thalidomide used for those who cannot use phototherapy
    – Azathioprine to treat sensitivity towards UV rays to treat photodermatitis
    – Antihistamines to tone down allergic reactions
    – Calamine lotions can be applied to get rid of the itchiness and irritation that accompany the rashes.
    – Anti inflammatory medications
  • Nutrition: Food that is eaten must be a balanced diet to ensure that they contain adequate amount of vitamins that help to treat and prevent photodermatitis. Antioxidant vitamins A, C, E, D and B – complex, magnesium, calcium, zinc, selenium, omega 3 fatty acids and alpha lipoic acid must be taken in correct amounts to treat such a condition.
  • Home remedies: Use of items commonly used for domestic purposes such as lavender oil, mustard oil, green tea, baking soda, aloevera and butter milk can be applied on the affected area to relieve the individual from the pain and itching, provide a soothing effect and reducing the inflammation of the affected area. Regular applications of these substances may quicken the healing process and provide comfort.

When to Visit a Doctor?

Minor allergies may appear and heal on their own within a short time. However, if a person notices a recurrent pattern of inflammation or rashes whenever he/she is exposed to the sun along with other complementary factors, it is best to seek help from a doctor. A doctor will be able to diagnose the case and provide the necessary treatment required. Also, it is advisable to visit a doctor at the earliest because photodermatitis could also be a sign of skin cancer.

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