Chemotherapy and Bruising: What to Expect and How to Cope

Chemotherapy can cause bruising for some people because it may lower platelet counts (thrombocytopenia), which makes it harder for blood to clot and easier to bruise or bleed. ^[1] You may notice bruises with little or no trauma, tiny red or purple spots on the skin (petechiae), bleeding gums, or nosebleeds during periods of low platelets. ^[2] Platelet counts often drop about 10 to 14 days after a chemotherapy cycle, and bruising or bleeding risk is higher during this window. ^[3] This side effect can occur across different regimens and may be more likely after multiple cycles over time. ^[4]

Why Bruising Happens

Platelets are blood cells that help stop bleeding by forming clots. Chemotherapy can temporarily damage the bone marrow where platelets are made, leading to a lower platelet count and increased bruising or bleeding. ^[1] When platelets are low, everyday bumps or minor injuries can cause visible bruises or prolonged bleeding. ^[1] It’s also common to see pinpoint skin spots (petechiae) or redness on the whites of the eyes during low-platelet periods. ^[5]

Common Signs to Watch For

• Unusual or easy bruising on arms or legs. ^[2]
• Small red or purple skin spots (petechiae) that don’t blanch when pressed. ^[2]
• Frequent nosebleeds or bleeding gums. ^[2]
• Blood in urine (brown/red) or black/tarry stools or red blood in stool. ^[2]
• Vomit that looks like coffee grounds or vomiting blood. ^[2]

If you notice these signs, especially more than one, it can suggest low platelets and higher bleeding risk. ^[2]

When to Contact Your Care Team

Seek urgent medical advice if you have heavy mouth or gum bleeding, a nosebleed that does not stop, blood in urine or stool, or vomiting blood. ^[2] Coughing up or vomiting blood should prompt immediate contact with your healthcare team. ^[6] Report new or worsening bruising, widespread petechiae, or eye redness, as these can be signs of bleeding related to low platelets. ^[5]

Practical Bleeding‑Precaution Tips

• Use a soft‑bristled toothbrush; avoid dental floss if your platelets are low to reduce gum bleeding. ^{[7] [8]}
• Shave only with an electric razor to lower the risk of cuts. ^[7]
• Be gentle with your skin; avoid vigorous rubbing or harsh towels. ^[9]
• Avoid contact sports, high‑impact exercise, and activities that could lead to falls or bumps. ^{[7] [10]}
• Blow your nose gently and avoid picking your nose to prevent nosebleeds. ^{[10] [6]}
• Prevent constipation (straining can cause rectal bleeding); avoid rectal suppositories or enemas when platelets are low. ^{[7] [10]}
• Check with your doctor before using anti‑inflammatory drugs like ibuprofen or aspirin, which can increase bleeding risk. ^{[4] [10]}
• Keep an eye on new skin changes such as petechiae; these usually fade as platelet counts recover, though it may take time. ^[8]

Timing and Monitoring

Many people experience the lowest platelet counts around days 10–14 after a chemo cycle, when bruising risk is highest. ^[3] Your team may monitor blood counts and advise precautions during this window, especially after several months of chemotherapy. ^[4] As platelets recover between cycles, bruising and petechiae often improve. ^[8]

Coping Day to Day

• Plan light, safe activities during low‑platelet days and avoid clutter or tripping hazards at home. ^[7]
• Wear protective clothing (long sleeves/pants) to reduce skin bumps and scrapes. ^[10]
• Keep nails short to avoid accidental scratching; treat dry skin to reduce cracking. ^[9]
• Hydrate and maintain a fiber‑rich diet to help prevent constipation. ^[10]
• Ask your care team about thresholds for extra precautions (for example, platelet counts under 50,000 often warrant added care). ^[5]

Medical Management Options

Your oncology team may adjust your chemotherapy schedule, recommend medications, or consider platelet transfusions in certain cases of significant thrombocytopenia and bleeding. ^[1] They will guide you on when lab checks are needed and what activity or medication changes are safest during low‑platelet periods. ^[4]

Summary Table: Bruising During Chemotherapy

Topic	Key Points
Cause	Chemo can lower platelet production in the bone marrow, reducing clotting and increasing bruising. [1]
Timing	Platelets often drop 10–14 days post‑chemo; risk may rise after months of treatment. [3] [4]
Warning signs	Easy bruising, petechiae, nose/gum bleeding, blood in urine/stool, coffee‑ground vomit. [2]
Immediate actions	Call your team promptly for heavy or persistent bleeding or blood in vomit/sputum/stool. [2] [6]
Precautions	Soft toothbrush, electric razor, gentle skin care, avoid high‑impact activities, no NSAIDs unless approved. [7] [8] [10] [4]
Recovery	Skin bleeding signs often fade as platelets recover between cycles. [8]

Key Takeaways

• Bruising during chemotherapy can be a normal side effect due to low platelets, especially 10–14 days after treatment. ^[3]
• Watch for and report bleeding warning signs promptly, and follow practical bleeding‑precaution steps to stay safe. ^{[2] [7]}
• Many symptoms improve as platelet counts recover, but your care team should guide monitoring and any treatment adjustments. ^{[8] [1]}