We report our therapeutic experience in a patient with complex regional pain syndrome (CRPS) related to brachial plexitis. A 16-year-old female suffered from excruciating burning pain and allodynia abruptly developed on left shoulder. Cervical MRI was normal. Electrodiagnostic findings were compatible with acute brachial plexopathy. Hand swelling, dystrophic color change, desquamation, and anhidrosis were displayed. Three-phase bone scan revealed increased radio-uptake on left upper extremity. The course of the disease was slowly progressive with wax and wane pattern. Pain became gradually intractable to all therapeutic modalities and medications. She gradually improved with long-term multimodal pain management. After 2 years of disease-free period, CRPS recurred and the extent was more severe than the first attack. We tried oral mexiletine, risedronate, high dose multi-vitamin, and leukotriene modulator which were effective in reducing pain and allodynia. Hand swelling gradually subsided and functional regain was obtained.