Phytophotodermatitis - Symptoms, Causes & Treatment
Medically reviewed by Dr. Anand S. Urhekar, MD, MD Pathology, Clinical Advisor · Last updated July 2026
A phototoxic skin reaction triggered when furocoumarin chemicals from certain plants — limes, lemons, celery, parsnip, fig, giant hogweed — contact the skin and are then exposed to ultraviolet light. It produces streaky redness and blistering in odd shapes matching drips or handprints, followed by long-lasting brown pigmentation.
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Quick Answer
Phytophotodermatitis is a sunlight-activated chemical burn caused by plant juices, most famously lime (the 'margarita burn'). Redness and blistering appear 24 hours after exposure in streaks or handprints, peak at 48–72 hours, then leave brown marks lasting weeks to months. Treatment is cool compresses, emollients, topical steroid for inflammation and strict sun protection while the pigment fades.
Symptoms
- Streaky or oddly shaped redness, often a drip or handprint pattern
- Burning rather than itching
- Blistering in more severe cases
- Onset about 24 hours after sun exposure, peaking at 48–72 hours
- Brown pigmentation persisting for weeks to months
Causes & Risk Factors
- Lime, lemon and other citrus juice
- Celery, parsnip, carrot tops, parsley, fig leaves
- Giant hogweed and wild parsnip
- Bergamot oil in perfumes
- Subsequent ultraviolet exposure — both elements are required
Treatment & Management
- Wash the skin promptly if exposure is noticed before sun contact
- Cool compresses and emollients
- Topical corticosteroid for inflamed areas
- Simple analgesia for pain; blister care as for a burn
- Strict sun protection until pigmentation fades
When to See a Doctor
See a doctor for extensive blistering, involvement of the face or genitals, signs of infection, or if you cannot distinguish it from cellulitis or a severe sunburn. Giant hogweed exposure to the eyes needs urgent care.
Frequently Asked Questions
Why is it called margarita burn?
Because squeezing limes for drinks in the sun is a classic trigger — juice runs down the hands and forearms, and the pattern of the rash follows the drips.
How long do the brown marks last?
The post-inflammatory pigmentation commonly lasts two to six months, occasionally longer. Daily sunscreen is the most effective way to help it fade.
Medical References
Information on this page is sourced from and verified against reputable medical resources:
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Medical Disclaimer: This information is for educational purposes only and is not intended as medical advice. The content on this page should not be used to diagnose or treat any health problem. Always consult with a qualified healthcare professional for proper medical evaluation, diagnosis, and treatment of your condition.