Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for severe trouble breathing, fainting, confusion, blue or grey lips, or heavy bleeding that does not stop.
If you already have Kaposi sarcoma, contact your care team promptly about worsening swelling, increasing pain, ulceration, bleeding, fever, persistent cough, abdominal symptoms, or difficulty eating.
Seek urgent medical care for coughing blood, vomiting blood, black tar-like stool, or rapidly worsening shortness of breath.
Arrange a routine appointment if you notice a new unexplained purple, red, brown, or dark skin patch that persists, grows, or multiplies.
You should also seek assessment for a lasting mouth lesion, new limb swelling, or changes in a previously diagnosed lesion.
Every sign above is quoted from the sofidex article on Kaposi sarcoma. If you are not sure, err upward — it is always reasonable to be checked.