Most itchy armpits are due to a possible fungal infection in the armpit, or it could be armpit eczema caused by a lot of sweating in the armpit. If it is underarm eczema and there is a lot of sweating, you can use topical creams, either Pirexone cream or Denide cream. If it is accompanied by folliculitis, you can also use trimethoprim cream or mupirocin cream. If this infection is more severe and the bacterial infection is more pronounced, oral roxithromycin can be used to reduce inflammation. If the fungal infection is more pronounced, you also need to combine it with Lanxessin cream and also keep the area clean and dry.