How you groom your armpit region -- if you do at all -- can influence the types of skin reactions you develop. There could be several causes for bumps developing on your armpits. The urgency of treating these bumps may be cosmetic, particularly if you are self-conscious during swimsuit season, but in most cases there are not serious implications of red bumps in this location.
Shaved armpit surfaces, or those that have recently been shaved and now show short hair follicles, can produce red bumps throughout the region of the armpit. Some of these may also have a visible hair follicle stuck in them. The bumps are usually red in color, and they may develop whiteheads at the top of the bumps.
Inflammation and swelling in the skin are common symptoms that may develop both in and around the red bumps. You may also experience skin sensitivity to varying degrees; some bumps may be extremely sensitive to the touch. Itching can also occur in both mild and severe cases. The discomfort caused by bumps under the armpits can make it difficult to function normally.
You may have developed a razor bump or multiple bumps if you have recently shaved your armpit hair. Rashes of various causes may also result from shaving, and folliculitis can develop in the hair follicles. Dermatitis may develop for a variety of reasons and may manifest itself in the form of bumps. You may also be experiencing acne in the armpits.
Razor bumps can be treated by removing the hair follicle end that has pierced and agitated the skin by gently lifting it out with a needle or a fine, thin object. Dermatitis can be relieved with a hydrocortisone cream; folliculitis needs to be treated with an antibiotic cream if it doesn't heal itself after a few days. The itching from a rash can be relieved with calamine lotion, but the rash itself should be treated depending on the cause. Acne can often be alleviated with proper hygiene, but other treatments may be required.
If you are unable to identify the cause of the red bumps underneath your armpits, visit a doctor or dermatologist to identify the cause -- it can be difficult to diagnose skin problems on your own, and some of them can have significant consequences if they go untreated. Consult a doctor if you develop other conditions or symptoms and are unable to identify a connection between these and your red bumps.