Phytophotodermatitis

Diagnosis: Phytophotodermatitis

Clinical History

Linear or bizarre-shaped erythema/blisters after contact with certain plants plus sun exposure. Classic history: lime squeezing outdoors, bartending, gardening.

Treatment

Self-limited. Cool compresses, topical corticosteroids. Post-inflammatory hyperpigmentation: sun protection, topical retinoids, hydroquinone. Resolves over weeks to months.

Differential Diagnosis

• Contact dermatitis • Child abuse (burn marks) • Berloque dermatitis • Drug-induced photosensitivity • Bullous insect bite reaction • Herpes zoster

Key Learnings

• Phototoxic reaction from furocoumarins (psoralens) in plants + UV exposure • Classic culprits: lime, lemon, celery, parsnip, giant hogweed, fig • "Lime disease" (not Lyme) — classic bartender or vacation scenario • Linear, bizarre-shaped erythema/vesicles followed by dramatic post-inflammatory hyperpigmentation • NOT immune-mediated — phototoxic (anyone will react with sufficient exposure) • Berloque dermatitis: from bergamot oil in perfumes — teardrop hyperpigmentation on neck

Tags: dermatology, kodachrome, Phytophotodermatitis