Hello Doctor.. I M Having Chronic Allergy For The Last

Hello doctor.. I m having chronic allergy for the last 3 months.. It started suddenly 24 hrs after taking yellow fever injection... Till now continuing.they r itchy red rashes .they usually start from elbows or thigh. Then gradually spread . I had taken l- hist medicines then montek lc as prescribed by doctor. Still no improvement.. Almost everyday they occur.. Please help.