: In chronic cases like HS, "sinus tracts" or tunnels can form under the skin between different lumps. Causes and Risk Factors
How do you know it isn't just a pimple or a swollen lymph node?
In hidradenitis suppurativa, lesions typically recur in the same armpit and may also appear in the groin, under the breasts, or on the inner thighs.
Blocked glands are not caused by poor hygiene and are not contagious. Contributing factors include: Hidradenitis suppurativa (HS) - NHS
A combination of dead skin cells, sebum (skin oil), and product residue from deodorants or antiperspirants can plug the duct.
: Lumps may eventually rupture and leak pus or blood, sometimes with an odor.