Black Spots on a Cat’s Rear End: What’s Normal & When to Worry

Have you noticed small dark spots or specks on the bare area under your cat’s tail and wondered if something’s wrong? Are those marks normal, or a sign of disease?

Black spots on a cat’s rectal opening are often harmless freckle-like pigmentation (lentigo), scent gland residue, or fecal debris. However, these spots can occasionally be caused by cysts or tumors. Have your veterinarian examine any raised, growing, inflamed, or bleeding spots.

Cats’ skin and fur can reveal a lot about their health. So when you see black spots on a cat’s “butt,” it’s good to understand whether they’re harmless or need attention. In this article, we’ll look at the most common causes of these spots then outline what to do if something seems unusual.

Some black spots on a cat’s rear are normal

Some black spots on a cat’s rectal opening are perfectly normal and nothing to worry about.

1. Natural pigmentation (lentigo).
Some cats, especially orange, cream, and silver ones, develop harmless dark freckles on their skin. Called lentigo, these spots are similar to human freckles and may appear on the lips, nose, eyelids, or in hairless areas on their rear end.

2. Normal scent gland openings.
You might also see small dark “beads” or dots near the lower part of the opening. These are the normal ducts of the scent glands, and the dark material is usually just dried gland secretion. If the area looks swollen or irritated, though, that can point to issues that need a vet’s attention.

3. Hygiene residue.
Sometimes the culprit is simply dried fecal matter or litter debris clinging to fur. This is more common in long-haired cats or those with limited flexibility. Good lighting usually makes the difference clear.

Abnormal black spots on a cat’s bottom

If the spots look raised, irregular, or are increasing in size or number, it’s time for a veterinary check. A simple biopsy may be needed to determine whether the lesion is harmless or something more serious.

Possible causes your veterinarian might consider include:

• Comedones (blackheads): Clogged hair follicles filled with oil or debris.
• Cystadenoma: Small, benign cysts formed by skin glands around the rectal opening, often bluish-gray.
• Dermal melanocytoma: Non-cancerous growths of pigment-producing cells.
• Malignant melanoma: Rare, aggressive tumors that can look similar to benign spots.

Avoid squeezing or manipulating any lumps. Doing so can trigger inflammation or, in the worst case, encourage abnormal cells to spread.

In closing

Dark spots beneath a cat’s tail are often harmless and are simply pigment, scent-gland openings, or hygiene debris. But some spots may indicate cysts or tumors. Because it’s hard to tell by sight alone, any new or changing spots should be examined by a veterinarian. Early attention can make all the difference for your cat’s long-term prospects.

Author: TB Thompson, DVM is a veterinarian with 20+ years of experience in clinics, emergency medicine, and community shelters. She started Natural Pets HQ to give pet owners accessible, trustworthy guidance written by a real vet.

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References

1. Loft, K. E., Soohoo, J., Simon, B., & Lange, C. E. (2022). Feline cystadenomatosis affecting the ears and skin of 57 cats (2011–2019). Journal of Feline Medicine and Surgery, 24(4), 351-358.
2. Stokking, L. B., & Campbell, K. L. (2004). 48. DISORDERS OF PIGMENTATION. Small Animal Dermatology Secrets E-Book, 352.