| Incorrect diagnosis |
| Treatment failure |
| Medication used incorrectly |
| Treatment regimen is too complex |
| Inadequate instructions |
| Medication not used because of parental or patient fear of medication side effects |
| Medication not available |
| Due to high cost |
| Not on formulary |
| Not available in the pharmacy |
| Allergic reaction to medication or skin care product (allergic contact dermatitis) |
| Exposure to irritants |
| Exposure to allergen (food or environmental) |
| Severe disease |
