Phytophotodermatitis is an allergic reaction secondary to a plant extract, in the presence of light.
The plant substance alone causes no reaction. Light alone causes no reaction. Light plus plant is necessary to produce the typical vesicular erythematous allergic contact dermatitis reaction.
Characteristically, clinical lesions are linear, secondary to plant sap being streaked across the skin.
Common causes of phytophotodermatitis are plants containing furocoumarins such as members of the celery and lime family as well as plants of the marigold family.
- Washing off residual sap is helpful. Care must be taken to remove all of it.
- Potent topical steroids applied topically result in clearing.
- There is frequently a residual post-inflammatory hyperpigmentation.