Blood in Your Underwear, Not on the Paper

Short answer: blood in your underwear rather than on the paper usually means something is still bleeding after you have left the bathroom, which most often points to an external hemorrhoid or an anal fissure. Hemorrhoids are the most common cause of blood in stool. But the ordinary causes and the serious ones look identical from where you are standing, so this needs a doctor either way. Not eventually. This one.

I found blood in my underwear on a completely ordinary day. Not straining, not in pain, not in the bathroom. Just there, in the middle of an afternoon, on fabric. After three years of blood on toilet paper that I had somehow talked myself into treating as normal, this was the thing that finally frightened me.

And then I waited another year before doing anything about it. That is the part I want you to skip.

Why is the blood in my underwear and not on the paper?

Because the bleeding is not only happening at the moment you wipe.

When blood shows up on paper, the timing lines up with the bowel movement, so it reads as “that thing that just happened.” When it shows up on fabric hours later, it means whatever is torn or swollen is still weeping a little after you have gone about your day. External hemorrhoids and fissures both do this. So does the irritation that comes with them, especially if the area is damp or gets rubbed.

Cleveland Clinic’s overview of rectal bleeding names hemorrhoids as the most common cause of blood in stool, with anal fissures listed right after, and notes that both usually follow straining and constipation. So statistically, the boring explanation is the likely one.

Statistically is doing a lot of work in that sentence, and I will come back to it.

What did it mean in my case?

Hemorrhoids and a fissure, from four years of constipation that started during lockdown in 2020. Less movement, worse eating, then constipation, then real pain. By the time the blood showed up on my underwear I had external hemorrhoids, itching, and a tear that kept reopening every time I went.

It resolved. Daily psyllium husk, actual meals instead of skipped ones, and better hygiene, and around four weeks in the fissure had healed and the bleeding had stopped.

But here is the thing about that ending. I did not know it was going to be that ending. For a year I assumed I knew what was bleeding and why, and I was right, and being right was luck rather than judgement. I had no way to distinguish my situation from the versions of this that need actual treatment, because from the inside they present the same way.

If you want the fuller version of that, it is in my story, and the practical differences between the two most likely culprits are in hemorrhoids versus fissures.

What should I be worried about?

Let me give you the honest version rather than the comfortable one.

Cleveland Clinic’s list of causes for rectal bleeding runs from hemorrhoids and fissures through inflammatory bowel disease, diverticulitis, infections, ulcers, polyps and colorectal cancer. Most of that list is treatable and much of it is common. But you cannot tell which one you have from a stain, and neither can I.

A few things that make this more urgent rather than less:

• Dark red, maroon, or black tarry stool. Bright red usually means the bleeding is low down in the colon, rectum or anus. Darker blood suggests higher up, and black tarry stool often points to the stomach.
• Bleeding that is heavy or does not stop. Cleveland Clinic says seek immediate care for that, and for bleeding that comes with severe pain or dizziness.
• Unexplained weight loss, ongoing fatigue, vomiting, or a change in your bowel habits that has stuck around.
• Age. Screening for colorectal cancer is recommended from 50 to 75 and offered starting at 45 by the US Preventive Services Task Force, which is worth knowing if you are in that range and have been putting off a conversation.

None of that is meant to frighten you at 2am. It is meant to be the thing I did not have, which was a clear reason to book something instead of a vague sense that I probably should.

Why see someone if it is probably just hemorrhoids?

Because “probably” is not a diagnosis, and because the appointment is smaller than you think.

Cleveland Clinic’s guidance is plain about this: contact a provider if you notice blood, and even if you think you know the cause, seeing someone is the best way to be sure it is nothing serious. They also say, in as many words, not to be embarrassed about it. This is a symptom clinicians see constantly and want to hear about.

What actually happens is usually questions and a digital rectal exam, which takes minutes. Depending on what they find and how old you are, they might suggest a look with an anoscope, a stool test, a flexible sigmoidoscopy or a colonoscopy. Most people do not get all of those.

I spent a year imagining that appointment as something enormous and humiliating. It was, in reality, an appointment. I never made it, and the only thing that came of not making it was four years of pain and a story I now write about so someone else does not repeat it. Everything on this site is my experience placed next to published sources. It is not medical advice and it is not a substitute for someone looking at you.

There is a short list of everything worth going in for if you want to check yours against it first. Two minutes, and then book anyway.

What can I do while I wait for the appointment?

Treating the constipation underneath is reasonable and does not interfere with being seen. Softer stools stop the re-tearing, which is what keeps the bleeding going.

Daily soluble fiber with a full glass of water every time is the piece that mattered most for me, though it is slow, and I have written about how long psyllium takes to work because the wait catches people out. Keep the area clean and then properly dry. Warm soaks help with the soreness. Do not push the bleeding out of your mind just because it eases off for a few days, which it will, and which is exactly how a year goes by.

One caution worth repeating: Cleveland Clinic’s own psyllium guidance says to stop and contact your care team if you have rectal bleeding. Fiber is not a reason to skip the appointment. It is what you do alongside it.

The one thing to do

Book it. Today if you can, this week if you cannot.

Write down when the bleeding started, what colour it is, whether it is on the paper or in the bowl or on your clothes, whether it hurts, and what your bowel movements have been like. That is the whole preparation. It takes five minutes and it makes the appointment twice as useful.

I know exactly what you are doing right now, because I did it for a year. You are reading pages like this one hoping one of them will tell you it is fine so you do not have to make the call. This page is not going to do that.