Patch Test (for Delayed Type Hypersensitivity)
A patch test is a diagnostic tool used to identify substances causing allergic contact dermatitis (Type IV hypersensitivity). Standardized concentrations of various allergens (such as metals, fragrances, preservatives, and rubber chemicals) are loaded onto adhesive patches and applied to intact skin, typically on the back. The patches are left in place for 48 hours, during which the patient must avoid wetting or disturbing the area. The patches are then removed, and the skin is evaluated for localized inflammatory responses (erythema, infiltration, papules, or vesicles) immediately after removal and again at 72 to 96 hours.
Dosage by Body Weight
Applied topically to the back by a healthcare professional. Dosing of allergens on the patch is pre-standardized and is not determined by body weight. The patch must remain dry and undisturbed for 48 hours prior to removal and interpretation.
- Body Weight
- Below 5 kg
- Dose
- Not recommended
- Frequency
- N/A
- Tracking Notes
- Patch testing is not routinely performed in infants due to extremely sensitive skin and lack of standardized safety data.
- Body Weight
- 5-7 kg
- Dose
- Not routine
- Frequency
- N/A
- Tracking Notes
- Should only be performed under the direct supervision of a pediatric allergist or dermatologist if contact allergy is strongly suspected.
- Body Weight
- 8-10 kg
- Dose
- Standard patch application (reduced panel size)
- Frequency
- Single application (48-hour wear)
- Tracking Notes
- Fewer allergens are typically tested at one time to accommodate the smaller surface area of a child's back.
- Body Weight
- 11-15 kg
- Dose
- Standard patch application (reduced panel size)
- Frequency
- Single application (48-hour wear)
- Tracking Notes
- Care must be taken to ensure the child does not scratch or dislodge the patches during the 48-hour period.
- Body Weight
- 16-20 kg
- Dose
- Standard patch application
- Frequency
- Single application (48-hour wear)
- Tracking Notes
- The allergen concentration per patch remains standard and does not change; only the number of patches may be restricted based on back size.
| Body Weight | Dose | Frequency | Tracking Notes |
|---|---|---|---|
| Below 5 kg | Not recommended | N/A | Patch testing is not routinely performed in infants due to extremely sensitive skin and lack of standardized safety data. |
| 5-7 kg | Not routine | N/A | Should only be performed under the direct supervision of a pediatric allergist or dermatologist if contact allergy is strongly suspected. |
| 8-10 kg | Standard patch application (reduced panel size) | Single application (48-hour wear) | Fewer allergens are typically tested at one time to accommodate the smaller surface area of a child's back. |
| 11-15 kg | Standard patch application (reduced panel size) | Single application (48-hour wear) | Care must be taken to ensure the child does not scratch or dislodge the patches during the 48-hour period. |
| 16-20 kg | Standard patch application | Single application (48-hour wear) | The allergen concentration per patch remains standard and does not change; only the number of patches may be restricted based on back size. |
Formulation
Purpose
Used to diagnose allergic contact dermatitis by identifying specific allergens triggering a Type IV (delayed-type) hypersensitivity reaction.
Generic Name
Allergen Patch Test PanelBranded Drug Names
Patch Test (for Delayed Type Hypersensitivity) is listed as a generic drug name. Common branded medicines that may contain the same active ingredient include:
Scheduled Drug
No. This medicine is generally not treated as a scheduled/prescription-only drug in common consumer references, but local rules may vary.