AB - Background: Hairdressers are exposed to irritants and allergenic compounds that may cause contact dermatitis, rhinitis and asthma. Objectives: In this paper we describe the case of a female, age 33 years, who developed contact dermatitis after 10 years of exposure to ammonium persulfate. Methods: After 7 months of progressively extensive and persistent skin lesions, respiratory symptoms appeared that were related to the occupational exposure (on-off test). SIDAPA and specific occupational patch test for hairdressers and occupational challenge with ammonium persulfate were performed. Clinical parameters of inflammation, ECP (eosinophil cationicprotein) and exhaled nitric oxide (FeNO) were detected before and after the specific bronchial challenge. Results: The patch test was positive to ammonium persulfate (++), and bronchial challenge for ammonium persulfate showed a significant late response (FEV1 decrease - 33%). Both FeNO and ECP showed a significant increase after 24 hours. Dermatitis, urticaria and angioedema occurred on the uncovered skin due to airborne contact. Topic steroids and anti- histaminic drugs resolved the clinical symptoms. Conclusions: Bronchial challenge is, in fact, considered to be the gold standard for the diagnosis of occupational asthma, although new inflammatory parameters can contribute to the diagnosis and can be useful for monitoring after a specific inhalation test with occupational agents. The described case summarizes the evolution from contact dermatitis to inhalation allergy, suggesting the occurrence of an allergic "march"for occupational allergy.