Mugwort

Mugwort is a widespread weed whose pollen is a major allergen in late summer and fall. It's in the same family as ragweed (Asteraceae) and the two cross-react significantly. Mugwort allergy is particularly notable for causing celery-birch-mugwort syndrome, a complex food allergy pattern. The pollen contains the allergen Art v 1, which triggers reactions in 10-14% of pollen allergy sufferers.

If you're allergic to mugwort pollen, you may also react to:

• Ragweed (same family, strong cross-reactivity)
• Celery, carrots, parsley, fennel (celery-mugwort-spice syndrome)
• Sunflower, chamomile, echinacea
• Birch (birch-mugwort-celery syndrome)
• Mango (tropical fruit cross-reaction)

• If celery makes your mouth itch during late summer, mugwort pollen cross-reactivity is the likely cause.
• Mugwort-celery-spice syndrome: allergy to mugwort, celery, carrots, and various spices (coriander, cumin, fennel) — these are linked.
• Mugwort season overlaps with ragweed. If fall is your worst season, you may be reacting to both.