Photodermatitis

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Photodermatitis

Photodermatitis happens when certain plant chemicals cause the skin to become inflamed following exposure to sunlight

This condition happens when a person has exposure to sunlight after coming into contact with a plant to which they are sensitive.

What are the symptoms?

The symptoms of phytophotodermatitis usually begin 24 hours after exposure and peak after 48–72 hours. The symptoms, which can be mild or severe, include:

large areas of blistering
itching
redness or discoloration
inflammation
pain
tenderness
a burning sensation
crusted patches of skin once the blisters have burst

The patches of blisters usually present in irregular shapes. The patterns represent the areas of the skin that became exposed to the chemical. For example, blisters in a drip pattern may result from exposure to fruit juice. Streaks may indicate that a person brushed their skin against a plant.

Causes

Phytophotodermatitis occurs when someone comes into contact with plant chemicals and then with sunlight. The symptoms typically arise after direct contact with the plant itself. Many plants and vegetables contain chemical compounds that cause sensitivity to sunlight. Such chemicals are known as photosensitizers. An example of a photosensitizer is a psoralen.

Some common plants that contain psoralen include:

parsley
carrot
celery
fig
citrus fruits
garden rue
breadnut
meadow grass
parsnip

Psoralen may also be present in some fragrances and some plant oils, such as the oil of bergamot. On exposure to UVA light, psoralen causes photochemical reactions in the skin. These responses damage skin cells and cause cell death, leading to the symptoms of phytophotodermatitis.

Treatment

Most cases of phytophotodermatitis clear up with minimal intervention. However, treatment is available to reduce pain and shorten the duration of symptoms. Treatment options include:

Avoiding reexposure: It is important to take steps to avoid the plant that caused the skin reaction. For many individuals, this may be enough to alleviate the symptoms.
Avoiding other skin irritants: It may be helpful to wear cotton clothing and avoid the use of harsh detergents, soaps, and personal care products that may make the symptoms worse.
Cold compresses: Placing a cool washcloth on the affected area provides relief.
Topical creams: Applying soothing ointments, lotions, and creams to the skin may reduce swelling and itching.
Corticosteroids: Topical steroidal creams will reduce inflammation and itching.
Over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs include aspirin and ibuprofen, and they may help reduce pain and swelling.
Prescribed medications: A doctor may prescribe oral corticosteroids or antihistamines for severe symptoms.
Reducing sun exposure: Spending less time in the sun, especially when UV rays are at their strongest, may help prevent hyperpigmentation from becoming even darker. Also, a person should always wear sunscreen when they cannot avoid sun exposure.

Risk factors

Phytophotodermatitis can affect anyone. However, several factors may increase a person’s risk of experiencing it.

The risk factors include:

exposure to certain plants and plant-based products
using perfumes or oils that contain particular plant chemicals
sunny weather
engaging in certain activities