Complications & HS
The main complication is scarring of the skin and deeper tissues. In severe cases, this can cause swelling of the arm (if the armpit was affected) or of the leg (if the groin was affected). This is called lymphoedema. This means that the fluid (lymph) drainage from the limb is affected and the fluid builds up, causing the swelling. It is a difficult problem to treat and cure; often, tight elastic compression garments have to be worn long-term.
Other complications include:
A general feeling of being unwell and tired (malaise).
Depression.
Long-term (chronic) infection leading to problems such as anemia, kidney problems, and low levels of protein in the blood.
Joint pains and inflammation (arthropathy).
Skin cancer. This is rare but has been reported in very severe long-term hidradenitis suppurativa.
Fistula formation. A fistula occurs when channels, called sinus tracts, tunnel into other parts of the body, such as the bowel or bladder (this is rare).
