| Application site reaction | |
|---|---|
 | |
| 52-year-old male patient with severe contact dermatitis and severe pain at the application site of a 15mcg/hr buprenorphine transdermal (Norspan) patch. | |
| Specialty | Dermatology |
Application site reactions are reactions to medical treatments which occur at the site of application. An example is skin reactions to transdermal patches.
These reactions may be caused by:
- Irritant (non-allergic) reactions — the most common type, caused by direct skin irritation from adhesives, solvents, or the drug itself..
- Allergic reactions — usually allergic contact dermatitis, a delayed hypersensitivity immune response to an allergen such as patch adhesive, excipients, or the active drug.
- Mechanical forces
Some application site reactions are neither allergic nor irritant in immunologic terms, but result from friction, occlusion, pressure, or repeated removal trauma.
- Local inflammatory injection unrelated to allergy
Implants may trigger localized redness, swelling, pain, or induration due to nonspecific inflammation rather than allergy.
