Phytophotodermatitis: What is ‘Lime Disease’ and How to Prevent It

A burning rash after handling limes or other citrus fruits? You might be experiencing phytophotodermatitis, a common skin reaction often nicknamed “lime disease.” This condition isn’t caused by bacteria like Lyme disease, but by a phototoxic reaction triggered by certain plant compounds and sunlight.

What is Phytophotodermatitis?

Phytophotodermatitis is a skin inflammation that occurs when the skin comes into contact with certain plants – most commonly citrus fruits like limes, lemons and oranges – and is then exposed to ultraviolet (UV) radiation from sunlight. The reaction is caused by chemicals called furocoumarins, present in these plants. These substances become toxic when activated by UV light [1].

The resulting skin reaction resembles a sunburn, but it occurs specifically in areas where the plant juice has touched the skin. Symptoms typically develop 24 to 48 hours after exposure [2].

Symptoms of Phytophotodermatitis

Common symptoms include:

• Redness (erythema)
• Blisters
• Burning sensation
• Swelling
• In some cases, prolonged skin discoloration (hyperpigmentation)

A recent case reported in The Latest England Journal of Medicine involved a man who developed a burning rash and blister on his thumb after squeezing limes for margaritas and then spending time outdoors [2]. The appearance of the rash can closely mimic a burn [1].

Which Plants Cause Phytophotodermatitis?

While limes and other citrus fruits are common culprits, several other plants can cause this reaction. These include:

• Wild parsnip
• Giant hogweed
• Celery
• Parsley
• Fig trees
• Certain wildflowers

It’s critical to note this isn’t an exhaustive list, and individual sensitivity can vary [3].

Treatment and Prevention

Phytophotodermatitis is usually self-limiting, meaning it resolves on its own over weeks or months. Though, several steps can be taken to manage symptoms and prevent complications:

• Wash the affected skin: Immediately wash the area with soap and water to remove any remaining plant juice.
• Avoid sunlight: Protect the affected area from further sun exposure.
• Topical corticosteroids: A doctor may prescribe topical corticosteroids to reduce inflammation and relieve itching.
• Moisturizers: Keeping the skin moisturized can help with dryness and promote healing.

While treatment can alleviate symptoms, it doesn’t shorten the duration of the reaction. In some cases, hyperpigmentation may persist for months or even years.

When to See a Doctor

Consult a healthcare professional if:

• The rash is severe or widespread.
• You develop signs of infection, such as pus, increased pain, or fever.
• The rash doesn’t improve after several weeks.

Key Takeaways

• Phytophotodermatitis is a skin reaction caused by contact with certain plants and subsequent sun exposure.
• It’s often called “lime disease” but is not related to Lyme disease.
• Symptoms resemble a sunburn and include redness, blisters, and burning.
• Treatment focuses on symptom relief and sun protection.
• Prevention involves avoiding contact with photosensitizing plants or protecting skin after contact.