Most dogs with noticeably loose or wrinkly skin inherited it. Specific genes control how much a dog’s body produces certain skin components, and in some breeds, those genes are dialed way up. The result is folds, rolls, and droopy skin that can look like your dog is wearing a suit two sizes too big. While it’s almost always a normal breed trait, understanding why the extra skin is there helps you keep it healthy.
Genetics Are the Primary Reason
If your dog has a lot of extra skin, the answer is overwhelmingly genetic. Wrinkles and loose folds are a characteristic feature of certain breeds, driven by genes that influence how skin and connective tissue develop. Breeds known for this trait include Shar-Peis, Neapolitan Mastiffs, Bullmastiffs, Bloodhounds, Basset Hounds, English Bulldogs, and several other mastiff-type dogs.
The Shar-Pei is the most extreme example, and researchers have actually identified exactly what’s happening at the molecular level. Shar-Peis carry a duplication of DNA near a gene called HAS2, which produces hyaluronic acid, the same moisture-retaining substance used in human skincare products. In Shar-Peis, this gene is overexpressed, meaning their skin cells churn out far more hyaluronic acid than other breeds. The result: their blood levels of hyaluronic acid run two to five times higher than normal dogs. All that extra hyaluronic acid accumulates in the skin, thickening it and creating those deep, signature wrinkles. Researchers have even coined a term for it: hyaluronanosis.
The more copies of this DNA duplication a Shar-Pei carries, the more hyaluronic acid their body produces and the wrinklier they become. This is why some Shar-Peis (the “meatmouth” type) are dramatically more wrinkled than others of the same breed.
Extra Skin Served a Working Purpose
These breeds didn’t end up wrinkly by accident. Loose skin gave working dogs real advantages. Many mastiff-type breeds were historically used as war dogs, guard dogs, and fighting dogs, and their excess skin directly protected them in combat. A Neapolitan Mastiff’s heavy neck folds, for example, shielded the jugular vein. When an attacker, whether another dog or even a horse, snapped at the throat, it would grab a mouthful of loose skin rather than reaching the vulnerable blood vessels underneath. The skin would slip free of the bite without causing serious injury.
Shar-Peis were used as farm guard dogs and hunters in ancient China, and their loose skin worked the same way. If another animal grabbed hold during a fight, the Shar-Pei could still twist and turn within its own skin to fight back or escape. Bloodhounds, on the other hand, developed loose facial skin and long ears for a different reason entirely: those drooping folds help funnel scent particles toward the nose during tracking.
When Extra Skin Signals a Medical Issue
In rare cases, unusually loose or fragile skin in a dog that isn’t a wrinkly breed can point to a genetic condition called cutaneous asthenia, the canine equivalent of Ehlers-Danlos syndrome in humans. This is a group of inherited disorders where collagen, the protein that gives skin its strength, doesn’t develop properly.
Dogs with this condition are born with it, but owners often don’t notice until the dog starts getting skin injuries. The hallmark signs are skin that tears easily from minor bumps or scratches, wounds that bleed very little, and skin covered in multiple scars. Some affected dogs also have unusually flexible joints or develop hernias. The skin’s tensile strength can be reduced by as much as 40-fold compared to a healthy dog. If your dog’s skin seems abnormally stretchy and tears or bruises with very little contact, that’s worth investigating rather than assuming it’s just a cosmetic quirk.
Health Risks of Deep Skin Folds
The biggest practical concern with extra skin is skin fold dermatitis. Deep wrinkles trap warmth and moisture, creating the perfect environment for bacteria and yeast (particularly a type called Malassezia) to multiply on the skin’s surface. This is the same basic process that causes skin irritation in human skin folds. The condition can develop between facial wrinkles, around the tail base, along the lips, or in any area where skin consistently presses against skin.
Early signs include redness, a musty or sour smell coming from the folds, and brownish or yellowish discharge. Your dog may scratch or rub the affected area. The skin inside the fold can look raw, inflamed, or unusually moist. Left untreated, the irritation can progress to a genuine bacterial or fungal infection that’s harder to resolve.
Keeping Wrinkly Skin Clean and Healthy
Routine cleaning is the single most important thing you can do for a wrinkly dog. The goal is simple: keep the folds dry and free of debris. Gently wipe between each skin fold with a soft cloth or antimicrobial wipe designed for dogs. How often depends on your dog. Some dogs need daily cleaning, especially in facial folds, while others do well with a few times per week. Hot, humid weather increases the frequency you’ll need.
After wiping, make sure the folds are thoroughly dry. Moisture left sitting in a fold is what starts the cycle of irritation and microbial overgrowth. Some owners use a light dusting of cornstarch-based powder to absorb residual moisture, though you want to avoid anything heavily fragranced that could irritate the skin further. Pay particular attention to facial folds (especially in flat-faced breeds where folds sit near the eyes), lip folds, tail pockets, and any deep wrinkles along the body.
If you notice persistent redness, a worsening smell, or discharge that doesn’t clear up with regular cleaning, that typically means the surface bacteria or yeast have gotten ahead of what basic hygiene can manage. Treatment usually involves medicated wipes or topical products that address the microbial overgrowth, sometimes combined with a short course of anti-inflammatory treatment to calm the irritated skin. Maintenance cleaning two to three times per week after the flare resolves helps prevent recurrence.
The Shar-Pei Fever Connection
For Shar-Pei owners specifically, there’s an additional wrinkle, so to speak. The same genetic duplication that causes excess hyaluronic acid and heavy wrinkling is also linked to a periodic fever syndrome. Dogs with a high copy number of the HAS2 duplication are significantly more likely to experience recurring episodes of fever and swelling, particularly around the joints. This means the wrinkliest Shar-Peis tend to be at the highest risk. If your Shar-Pei runs unexplained fevers, especially with swollen hocks (ankle joints), the underlying cause is likely related to the same genetics responsible for their skin.