Contact%20dermatitis%20(pediatric) Diagnosis
Diagnosis
Allergic Contact Dermatitis (ACD)
- An immunologic cell-mediated skin reaction to exposure of antigenic substances; patch test positive
Irritant Contact Dermatitis (ICD)
- A non-immunologic skin reaction to skin irritants; patch test negative
Allergic Contact Dermatitis (ACD) | Irritant Contact Dermatitis (ICD) | |
Risk group | Genetically predisposed | Everyone |
Mechanism of response | Immunologic response: Delayed hypersensitivity reactions | Non-immunologic: Physical and chemical alteration of the skin epidermis |
Nature of exposure | Can be very low concentration of low molecular weight hapten or allergen (eg metals, formalin, epoxy) after 1 or many exposures | Normally high concentration of organic solvent or soaps, etc after few to many exposures |
Onset | Usually hours to days | Usually minutes to hours |
Distribution | May correspond exactly to contactant (eg elastic waist band, wristband); may also be disseminated due to autosensitization | Distinct borders in acute ICD
Indistinct borders in chronic ICD Usually localized to area with exposure to irritant |
Clinical manifestation | Usually in subacute and chronic phase | Usually in acute phase |
Diagnostic test | Based on positive patch test or usage test | Based on trial of avoidance or negative patch test |
Management | Complete avoidance of allergens Nonpharmacologic and pharmacologic therapy |
Protection and reduced incidence of exposure Nonpharmacologic and pharmacologic therapy |
History
Determine trigger factors based on:
- Medical history
- Usually identifies the sensitizing agent or allergens in only 10-20% of cases
- Questioning the relationship between skin condition and:
- Date of onset
- Exposure to diapers, hygiene products, personal skin care products, sunscreens, clothing or fabrics with dyes, medications, pets, school supplies, sports uniform, nickel-containing items
Physical Examination
- Determine trigger factors based on physical examination
Laboratory Tests
Patch Test
- The gold standard for diagnosing allergic contact dermatitis (ACD)
- Result reading should be done 48 hours after application
- Allot another 30 minutes after application for erythema to settle after removing the tape/chamber
- Second reading must be done 3-7 days after initial patch application
- Results should be correlated with patient’s medical history
- Should only be done to children <6 years old with high degree of clinical suspicion for specific allergens
- Recommended in cases where symptoms persist despite avoidance of trigger factors and topical therapy
- Not recommended as a diagnostic test for irritant contact dermatitis (ICD)
- Avoid when allergic contact dermatitis (ACD) is active, flaring and covers >25% of body surface area (BSA)