The most common cause of a small fleshy growth under the armpit is a wart. A so-called wart is actually a viral infection that can cause being infected in the shower. Warts are usually painless and do not have localized itching, just a growth of fleshy tissue. The second common cause of warts is a localized laceration of the skin that has been chronically irritated and caused by overgrowth of the local tissue, thus raising the subcutaneous or skin causing the shape of a bud. This is a condition we call keloid hyperplasia.