Specific immunotherapy for patients allergic to hymenoptera stings is known as a safe and effective treatment. Side effects can occur, usually as local or mild systemic allergic reactions.We report a 16-year-old girl undergoing bee venom immunotherapy who suffered anaphylactic reactions after allergen injections. 24 hours after her last bee venom injection she presented with sudden inset of severe pain affecting her left shoulder, chest wall and left arm. A few days later pain sub-sided and muscular weakness in her left arm and hand occured as well as shortness of breath. Electrophysiological findings revealed signs of axonal damage of affected nerves of the brachial plexus. Lung function tests showed a reduction of the forced vital capacity. The clinical diagnosis of neuralgic amyotrophy (NA) with phrenic nerve involvement could be confirmed by ultrasound. The patient underwent a corticosteroid treatment in the acute phase and intensive physical therapy in the later course. Weakness of the left arm and diaphragmatic paralysis recovered within a year. Venom immunotherapy has been stopped. We assume an association between brachial plexus disorder and venom immunotherapy.