Are you paying close attention to your skin? Believe it or not, your skin might be sending you the first warning signs of colon cancer—well before any abdominal symptoms show up! Most people know to watch out for things like changes in bowel habits or abdominal pain, but a few rare skin changes are also important red flags. In this article, I’ll walk you through three weird skin signs that could signal colon cancer, so you know exactly what to look for and when to seek medical advice.
Key Takeaways
- Colon cancer is surprisingly common and can sometimes show up on your skin before anywhere else.
- Three rare skin changes—Sudden Outbreaks of Seborrheic Keratosis, Malignant Acanthosis Nigricans, and Acquired Hypertrichosis Lanuginosa—can be early warning signs of colon cancer.
- Recognizing these signs early (especially if they arise suddenly) can make a big difference in early cancer detection.
1. Sudden Outbreak of Seborrheic Keratosis (Lesser-Trelat Sign)
Have you ever heard of seborrheic keratosis? These are those common, waxy, raised skin growths that most people get as they age. In most cases, they’re annoyingly harmless. But if you or a loved one suddenly develops a LOT of these all at once or notices existing spots growing quickly—and especially if they become itchy—this could be a sign of something more serious.
This unusual occurrence is known as the Lesser-Trelat sign. While seborrheic keratosis usually appears slowly over years, the key point is that the sudden, rapid onset of many new lesions, especially if accompanied by itchiness, is a potential red flag for underlying cancers such as colon cancer or other GI malignancies. This sign is rare, but it is hugely important to notice, as it may be underreported or mistaken for typical age-related skin changes. The bottom line: if you see an explosion of these spots, don’t ignore it—talk to your doctor.
2. Malignant Acanthosis Nigricans
Acanthosis nigricans is a skin change where your skin becomes darker, thicker, and often has a velvety feel, usually found in body folds like the armpits, groin, or neck. Most of the time, it’s linked to obesity, diabetes, or insulin resistance. But here’s the weird twist: it can also be an early sign of colon cancer—especially a type called colorectal adenocarcinoma—if it appears suddenly or gets much worse for no clear reason.
While common among people with weight or metabolic issues, in rare cases acanthosis nigricans appears in people with GI cancers, sometimes even before any other symptoms show up. If you (or someone you care for) develops new or rapidly worsening, velvety, dark skin patches for no apparent reason, especially if they aren’t overweight or diabetic, it’s time to get checked out. Both this and the Lesser-Trelat sign can even happen together.
3. Acquired Hypertrichosis Lanuginosa (Sudden Fuzzy Hair Growth)
This last sign is the rarest, but arguably the weirdest. Hypertrichosis lanuginosa is when fine, soft, unpigmented “lanugo” hair (like the kind newborns have) suddenly starts growing on parts of the body, including the face, ears, nose, trunk, and limbs—except the palms, soles, or perineum. While this fuzzy hair growth can be linked to metabolic or hormone problems, in very rare situations it can point to internal cancers like colon (as well as lung or breast) cancer.
Here’s what’s even stranger: this new hair growth might show up as much as two and a half years before the actual tumor is found. If you, or a friend or family member, suddenly gets much hairier without explanation, or starts growing soft baby-like hair in new places, this is a sign to have a medical check-up.
Other Common Signs of Colon Cancer (Just So You Know)
While today we’re focusing on rare skin-related clues, remember that colon cancer more frequently presents with:
- Abdominal pain (the most common symptom)
- Changes in stool shape (like pencil-thin stools)
- Constipation, diarrhea, or alternating bowel habits
- Family history, low fiber diet, older age, and a history of inflammatory bowel disease (like Crohn’s or, especially, ulcerative colitis) all raise your risk
Why Do These Skin Signs Happen?
All three of these strange skin changes are considered “paraneoplastic syndromes,” meaning they result from substances released by the tumor or the body’s immune reaction to cancer. The exact reason why colon cancer causes these particular rashes and hair changes isn’t totally understood, but the association is well documented in scientific cases.
What Should You Do?
While these skin signs are rare—and for most people, benign skin changes have nothing to do with cancer—they’re important to know about, especially if they show up suddenly or seem “off.”
If you or someone you know develops any of these odd skin changes, don’t panic, but don’t ignore them either. Bring them up with your healthcare provider, especially if there’s also a family history of cancer, digestive issues, or unexplained symptoms. Early detection can make a crucial difference.
Conclusion
Your skin is your largest organ, and sometimes it shouts warnings even when the rest of your body feels fine. Pay attention to sudden changes—especially the weird ones we covered today. If something looks or feels different, always trust your gut and check with your doctor. Keep an eye on your skin, because it just might help catch a bigger problem early!
Source: JJ Medicine