| Allergen group | Mode of exposure* |
| Grass pollens | Inhalation (outdoor) |
| Weed pollens | Inhalation (outdoor) |
| Tree pollens | Inhalation (outdoor) |
| Mold (hyphae-spores) | Inhalation (outdoor and indoor) |
| Dust mite fecal material | Inhalation (indoor) |
| Animal proteins (epidermal and serum) | Inhalation (indoor) |
| Foods | Ingestion |
| Insects | Inhalation or injection (indoor and outdoor) |
| Hymenoptera venoms | Injection |
| Parasites | Ingestion or injection |
| Drugs | Injection or ingestion |
| Occupational | Contact or inhalation or ingestion |
