What Does a Pea-Sized Lump in the Armpit Mean?

By Staff WriterLast Updated Apr 1, 2020 10:41:21 AM ET

According to the Mayo Clinic, pea-sized lumps in the armpit are a symptom of hidradenitis suppurativa, a condition in which the hair follicles become blocked. The cause of hidradenitis suppurativa is unknown, but the condition is linked to hormonal fluctuations and excess weight. Symptoms include pea-sized lumps under the arm, blackheads, leaking sores or tender red bumps in the armpit, between the thighs and underneath the buttocks.