Gene profiling in active dermatitis lesions strengthens the diagnosis of allergic contact dermatitis

BACKGROUND

Distinguishing between allergic and nonallergic forms of Contact Dermatitis (CD) is challenging and requires investigations based on patch-testing. Early detection of allergy biomarkers in active CD lesions could refine and simplify the management of CD patients.

OBJECTIVE

To characterize the molecular signatures of active CD lesions.

METHODS

We studied the expression of 12 allergy biomarkers by qRT-PCR in active lesions of 38 CD patients. Allergic CD (ACD) was diagnosed based on patch test (PT) results and exposure assessment. Molecular signatures of active lesions, as well as positive PT reactions, were compared with those of reference chemical allergens and irritants.

RESULTS

Nineteen of the 38 CD patients reacted positively upon patch-testing and exposure assessment confirmed ACD diagnosis for 17 of them. Gene profiling of active CD lesions revealed 2 distinct molecular patterns: patients harboring signatures similar to reference allergens (n = 23) or irritants (n = 15). Among the 23 patients with an "allergy signature," we found the 17 patients with confirmed ACD, while no culprit allergen was identified for the 6 other patients. Interestingly, the 15 patients without biomarker induction had negative PT, suggesting that they developed nonallergic CD reactions.

CONCLUSION

Molecular signatures from active skin lesions may help to stratify CD patients and predict those suffering from ACD.

Impétigo streptococcique apparu sur les sites d’application du tacrolimus chez une jeune atopique

BACKGROUND

We report a case of staphylococcal impetigo in a girl treated with tacrolimus ointment (Protopic) for atopic dermatitis.

OBSERVATION

A 15 year-old girl was receiving treatment with tacrolimus 0.03% (Protopic) for an episode of atopic dermatitis. On reduction of applications of tacrolimus, a vesicular-pustular rash appeared and was treated with pristinamycin and valaciclovir. At the end of antibiotic and antiviral therapy, the vesicular-pustular rash recurred while the goal was receiving treatment once more with tacrolimus ointment 0.1%. The bacteriological and virological skin samples revealed B-haemolytic streptococcus group A. The negative results for cutaneous virological samples ruled out Kaposi-Juliusberg syndrome and a diagnosis of staphylococcal impetigo was made. The intrinsic imputability of tacrolimus was I3 (C3 S2).

DISCUSSION

The most obvious specific feature of this impetigo was its limitation to areas of eczema treated by application of tacrolimus. In prospective studies in large patient cohorts, tacrolimus ointment has been associated with two types of adverse effect: local irritations and skin infections chiefly caused by Staphylococcus aureus. To date, there have been no reports in the literature of impetigo due to haemolytic B streptococcus following application of tacrolimus. Because of its immunodepressant effect, tacrolimus ointment may result in increased incidence of skin infections even though a number of studies have shown a reduction in such infections.