Heat rash: When sweat ducts don’t have the opportunity to “breathe” (which often happens in warm environments), they trap perspiration beneath the skin and can create lumps, bumps, and ...

They're located throughout the body in the armpits (called axillary lymph nodes), the groin, neck and chest. The nodes can become swollen and painful, usually when the body is fighting off infections.

Heat rash may also look different from other rashes you've had in your life. For example, it can look like a blister or just groups of bumps.

The rash appears 2 to 3 days after the infection and presents as small, raised, blanching rashes that feel like sandpaper. The rashes begin in the trunk, armpit, and groin, and then spread to the ...

Armpit itching is caused by myriad issues, from contact dermatitis to cancer. Here are the most common conditions, treatments, and when to see a doctor.