Summer, with its lush greenery and abundant sunshine, often brings with it a particular skin problem. When the skin comes into contact with certain plant chemicals and is then exposed to sunlight, it can result in a condition called plant-induced photosensitivity dermatitis, also known as phytophotodermatitis.
The name comes from “phyto,” meaning plant, “photo,” meaning light, and “dermatitis,” meaning inflammation of the skin. Symptoms of phytophotodermatitis include skin inflammation, itching, and blistering.
What are the symptoms of phytophotodermatitis?
Phytophotodermatitis occurs when exposed to plant chemicals and then exposed to sunlight. Symptoms typically begin 24 hours after contact and peak between 48-72 hours. Symptoms can range from mild to severe and may include:
- Blistering
- Itching
- Redness
- Inflammation
- Pain
- Tenderness
- Burning sensation
The range of dermatitis on the skin usually has an irregular shape, representing the area of the skin exposed to the chemical. For example, droplet-shaped marks may be due to contact with fruit juice, while a stripe may indicate contact with a plant. The initial symptoms typically subside after 7-14 days, and the skin may show signs of post-inflammatory hyperpigmentation, which is a darkening of the skin. This phase of phytophotodermatitis may last for several weeks or months.
Some people may only experience very mild inflammatory reactions after exposure to sunlight, or may not even notice any inflammation at all. Post-inflammatory hyperpigmentation may be their first symptom of plant-induced photosensitivity dermatitis. Wet skin, sweat, and heat can exacerbate initial symptoms, while exposure to sunlight can cause the skin’s hyperpigmentation to become worse.
Causes
Citrus fruits and oils from citrus fruits may trigger plant-induced photosensitivity dermatitis. When exposed to plant chemicals and subsequently exposed to sunlight, phytophotodermatitis can occur. Many plants and vegetables contain compounds that are sensitive to sunlight, known as photosensitizers. One example of a photosensitizer is psoralen.
Common plants that contain psoralen include:
- Wild parsnip
- Parsley
- Carrots
- Celery
- Figs
- Citrus fruits
- Grass
Additionally, it may be present in:
- Certain perfumes
- Certain plant oils, such as bergamot oil
When exposed to UVA rays, psoralen causes a skin phototoxic reaction. These reactions damage skin cells and cause cell death, leading to the aforementioned symptoms.
Risk factors
Anyone, regardless of gender, age, or race, can be affected by phytophotodermatitis. However, certain factors may increase the risk of developing the condition.
These include:
- Contact with certain plants and plant products
- Use of perfumes or oils containing certain plant chemicals
- Sunny weather
- Engaging in activities such as gardening, cooking, camping, fishing, hiking, or outdoor sports
Certain professions may also increase the risk, such as:
- Farmers
- Gardeners
- Chefs and kitchen staff
- Bartenders
Phytophotodermatitis is often misdiagnosed and may be mistaken for:
- Atopic dermatitis
- Chemical burns
- Cellulitis
- Skin fungal infections
- Contact dermatitis
- Sunburn
Treatment
Most cases of plant-induced photosensitivity require little treatment and will heal on their own. Treatment aims to reduce pain and shorten the duration of symptoms. Treatment options include:
- Avoiding exposure to sunlight again – It is important to take steps to avoid plants that cause skin reactions. For many people, this is enough to relieve symptoms.
- Avoiding other skin irritants – Wearing cotton clothes and avoiding the use of irritating cleaners, soaps, and personal care products can prevent symptoms from worsening.
- Applying a cold compress – Placing a cold towel on the affected area can relieve pain.
- Topical creams – Using soothing creams, lotions, and ointments on the skin can reduce swelling and itching.
- Corticosteroids – Topical corticosteroid creams can reduce inflammation and itching.
- Painkillers – Non-steroidal anti-inflammatory drugs (NSAIDs) may help reduce pain and swelling.
- Prescription medication – In severe cases, a doctor may prescribe oral corticosteroids or antihistamines.
- Reducing sun exposure – Reducing exposure to ultraviolet light may help prevent pigmentation from worsening.
- Time – With time, skin pigmentation gradually fades.
Prevention of plant-induced photosensitivity
- Identify plants that are allergenic or irritating to the skin and take steps to avoid contact with the skin.
- Wash hands with soap and water after cooking, outdoor activities, or contact with plants. Washing helps remove plant chemicals from the skin.
- Cover the skin with appropriate clothing when outdoors and in forests.
- Wear gloves when gardening.
- Wear food preparation gloves when cooking or cutting citrus fruits.
- Use sunscreen before skin exposure to sunlight.