Gingivitis is the medical term for inflammation of the gums. A type of periodontal disease, it’s caused by the long-term build-up of bacteria, mucus and food debris on exposed portions of the teeth.
The U.S. National Library of Medicine offers this list of warning signs for gingivitis:
Gums that bleed (check your toothbrush after brushing for blood).
Gums that appear bright red or purple.
Gums that are sore or tender to the touch.
Sores inside the mouth.
Swelling of the gums.
Gums that appear shiny.