Why does dengue fever cause easy bruising?

Bruises form when small blood vessels leak beneath the skin. Platelets help the body form an early plug at a bleeding site, and dengue can lower platelet levels or affect how the blood vessels behave. This can make bruises appear after minor knocks or without a remembered injury. Easy bruising is a common presentation of dengue fever.

Bruising does not establish the cause by itself. Medicines that affect clotting, liver disease, blood disorders, nutritional problems, injury, and other infections can also be involved. In a person with dengue symptoms or confirmed dengue, new bruising should be reported to the treating clinician because it may need assessment alongside the rest of the illness.

Avoid contact sports, heavy lifting, and activities likely to cause falls or knocks. Use a soft toothbrush and take care when shaving. Do not take aspirin or anti-inflammatory pain medicines unless a clinician has told you they are appropriate, as they can increase bleeding risk. Rest, drink fluids if tolerated, and follow any monitoring instructions you have been given.

Photographing a new bruise with the date, if you are comfortable doing so, can help show whether it is spreading. Note nosebleeds, gum bleeding, heavier than usual menstrual bleeding, dark stools, vomiting, abdominal pain, dizziness, and changes in urination to report clearly.

Seek urgent medical care for bleeding that does not stop, blood in vomit, urine, or stool, black tar-like stools, severe abdominal pain, repeated vomiting, fainting, severe weakness, confusion, breathing difficulty, cold clammy skin, or very little urine. These symptoms can accompany a serious change during dengue illness. Seek prompt clinical advice for unexplained new bruises or any increase in bruising when dengue is suspected.

Ask whether blood tests are needed, which medicines and supplements to avoid, what activities are safe, and exactly which bleeding symptoms require emergency care. Tell the clinician about blood-thinning medicines, herbal products, prior bleeding problems, and any pregnancy.