Laser-assisted penetration of allergens for patch testing

Background. Patch-test patients often complain of itching and inconvenience. Objective To demonstrate (1) the usefulness of laser-assisted alteration of the stratum corneum to enhance allergen delivery and (2) patient satisfaction with this procedure. Methods: The LAD-01 (erbium:yttrium-aluminum-garnet) laser unit was used to alter stratum corneum from patients with known sensitivity to nickel or Kathon CG. These allergens were then applied to the laser-pretreated sites for 60 minutes. Results were observed at 24, 48, and 96 hours and at 1 week. One patient who refused conventional patch testing was tested with an entire modified North American standard series tray with the laser patch-test technique. An additional patient with previously demonstrated positive atopy patch-test reactions to environmental organisms was retested with laser pretreatment to the same antigens. Results: Three of three patients known to be sensitive to Kathon CG and eight of eleven known nickel-sensitive patients had positive reactions at the laser-pretreated sites. The patient who was tested with the entire standard series demonstrated relevant positive reactions to formaldehyde and to a textile resin. One subject with known reactions to three environmental organisms reproduced patch-test responses with laser pretreatment. No irritant reactions were noted. Patients reported no pain. Conclusion: With further modification, laser pretreatment may improve patient convenience and decrease irritant test reactions owing to occlusion.