The specific inhalation challenge (SIC), a workplace-related inhalation exposure test, is used to identify allergic asthma when symptoms such as coughing, wheezing, or dyspnea occur at the workplace. Its use is risky. A cook (28 years old) has been complaining of rhinoconjunctivitis and contact urticaria while preparing seafood for 3 years. He continues to work, now wears gloves, no longer tastes fish dishes, and receives anti-obstructive therapy (ICS, LABA). Methacholine (MCH) testing for bronchial hyperreactivity (BHR) shows mild BHR (PD100;sRaw: 0.28 mg MCH), skin and blood tests show type I sensitization to fish and crustacean proteins. In SIC with fried shrimps, rhinoconjunctivitis, coughing and distance wheezing, FEV1 drop > 20%, sRaw increase to 9.6 kPa*s and angioedema occur. Since routine tests showed only a moderate BHR, the suspicion of an occupational disease was formulated very late in the medical examination process. Only the SIC showed the severity of the cook's bronchial asthma.