By the Pethocyn editorial team. Published October 29, 2026. Updated November 1, 2026. Sources are listed at the end of the article.

Skin signs can point to internal disease, and your vet looks for the cause. Superficial necrolytic dermatitis is one example. In this condition, sore, crusted skin is linked to a problem inside the body, most often in the liver, and less often a tumor in the pancreas [1][2]. It is uncommon in dogs, rare in cats, and seen mostly in older animals [1].

The condition is also called hepatocutaneous syndrome (“hepato” means liver, “cutaneous” means skin) [1]. A 2021 review of cases calls it a rare disease in dogs that is often fatal [5]. If your dog’s paw pads become crusted, cracked or sore, or sores appear on the face or genitals, see your vet. The skin often needs a biopsy, and your vet will look for an internal cause [1].

For other paw pad and nose problems, see our posts on paw problems in dogs and dry, crusty nose in dogs.

What causes it

In most affected dogs the trigger is a liver disease whose cause is usually not known; a hormone-producing pancreatic tumor called a glucagonoma is the less common cause [2]. In people the pattern is the other way round, with the tumor being the usual cause [2].

Either way, the blood ends up short of amino acids (the building blocks of protein). Researchers think the liver breaks them down too fast, or that high levels of the hormone glucagon drive this. The skin, which renews its cells quickly, then runs short of the protein it needs, and lesions form [1][2].

Other findings from studies:

  • A 2022 study of 41 dogs pointed to the liver changes as the earlier stage and the skin disease as the later stage of one syndrome. Most of these dogs (30 of 41) went on to develop the skin disease [4].
  • A 2016 study of 31 Shih Tzus traced a shared ancestry in 12 of the 18 dogs with pedigree records. The authors thought the condition may run in families in this breed, but it was also found in Shih Tzus with no known affected relatives [6].
  • A 2004 study described 11 dogs with the skin disease that had all been on long-term treatment with one anti-seizure medicine, and the authors called for more research into that medicine as a possible risk factor [7]. If your dog takes seizure medicine, your vet can tell you whether this applies. Do not stop or change any medicine on your own.

What you may notice

The skin changes tend to start where skin cells turn over fast: the paw pads, the face, the edges of the lips, eyes, anus and genitals, and pressure points [1][2]. You may see:

  • Crusts and open sores, with reddened skin around them [1].
  • Paw pads that are thickened, hard, cracked and painful [2].
  • Crusting on the nose, muzzle or chin [1][2].
  • Itching, especially of the paws, and pain that makes the dog move less or walk stiffly [1][2].

In the 2021 review, which pooled its own cases with published ones, every dog (143 of 143) had lesions on the paw pads or where skin meets the lining of the mouth, eyes or other openings [5]. In the 2016 Shih Tzu study, dogs were often tired, ate poorly, lost weight or were lame [6]. A dog can also seem well apart from the skin: in a 2024 case report, the dog was eating normally and its only known problem was the painful skin [1].

How it is diagnosed

  • Ruling out look-alikes: other diseases, such as autoimmune skin diseases, drug reactions and zinc-responsive skin disease, can produce a similar pattern, so tests are needed [1].
  • Blood tests and abdominal ultrasound: blood work often shows anemia, raised liver enzymes and slightly high blood sugar, and ultrasound of the liver and pancreas helps find the internal cause [1].
  • A “honeycomb” liver on ultrasound: in the 2021 review, this pattern showed up in 62 of 63 dogs with the liver-related form and in none of the dogs with the tumor-related form [5]. Other reports describe the same Swiss-cheese look [1][2].
  • Blood amino acid levels: low amino acids are a hallmark of the disease [2]. The 2021 review proposed that in a dog with typical skin lesions, measuring them can support the diagnosis without surgery, with ultrasound then helping to tell the liver form from the tumor form [5].
  • Skin biopsy: the 2024 case report authors advise that unless liver disease has been ruled out, a skin biopsy should be treated as necessary [1].

Treatment

Treatment is chosen by your vet and depends on the cause. Published reports describe supplying the missing amino acids, for example as infusions into a vein, together with diet changes planned by the vet [2][3]. If a tumor is found, your vet will discuss the options for it. Your vet will explain what is needed for the internal disease and for the skin, and how your dog will be monitored.

Outlook

Outcomes vary between studies:

  • Most published outcomes are poor, with average survival of about 3 to 6 months after diagnosis, though a few dogs have been reported to live more than 2 years [3].
  • A 2022 study of 41 dogs noted that long-term remissions, while seldom reported, may happen more often than once thought. The liver disease went into remission in 4 dogs. Median survival was 359 days for all causes of death and 557 days counting only deaths from this disease (range 1 to 1783 days) [3].
  • In the 2016 study of 31 Shih Tzus, median survival was 3 months (range 1 to 36 months) [6].

These are figures and statements about groups of dogs in particular studies. They do not prove that a treatment caused an outcome, and they cannot predict how one dog will do. Your vet can explain what the test results mean for your dog.

When to see your vet

See your vet if your dog has:

  • crusted, thickened, cracked or sore paw pads [1][2]
  • crusts, sores or redness on the face, lips, genitals or around the eyes [1][2]
  • a crusted nose or muzzle together with paw pad or skin lesions [1][2]
  • skin changes together with tiredness, poor appetite, weight loss or lameness [6]
  • any skin problem that keeps going or keeps getting worse

FAQ

Is this a skin disease or a liver disease?
Both. The skin lesions come from low blood amino acid levels, which in most dogs are linked to liver disease [1][2]. The liver changes may be present before the skin is affected [4].

Which dogs get it?
It is seen mostly in older dogs and rarely in cats [1]. A study of Shih Tzus suggested it may run in families in that breed [6].

Can my vet diagnose it without surgery?
Blood tests, blood amino acid levels and an abdominal ultrasound can point strongly to it [1][5]. A skin biopsy is still often needed to confirm it [1].

Is there treatment?
Treatment aims at the cause and at replacing the missing amino acids [2][3]. Your vet will plan treatment for your dog.

The bottom line

Skin signs can point to internal disease, and your vet looks for the cause. In superficial necrolytic dermatitis, liver disease or, less often, a pancreatic tumor lies behind crusted paw pads and sores on the face and genitals [1][2]. Have any ongoing skin change, especially on the paw pads of an older dog, checked by your vet.

This article is for general information and does not replace a visit to your veterinarian. If your dog’s paw pads crust or crack, contact your vet.

Sources

  1. Strichea AH, Hreniuc ȘL, Solcan G. Non-Invasive Paraclinical Diagnosis of Hepatocutaneous Syndrome in a Dog. Life (Basel). 2024;14(7):853. doi:10.3390/life14070853. Open access (CC BY). https://pmc.ncbi.nlm.nih.gov/articles/PMC11277621/
  2. Jaffey JA, Backus RC, Sprinkle M, Ruggiero C, Ferguson SH, Shumway K. Successful Long-Term Management of Canine Superficial Necrolytic Dermatitis With Amino Acid Infusions and Nutritionally Balanced Home-Made Diet Modification. Front Vet Sci. 2020;7:28. doi:10.3389/fvets.2020.00028. Open access (CC BY). https://pmc.ncbi.nlm.nih.gov/articles/PMC7004965/
  3. Loftus JP, Miller AJ, Center SA, Peters-Kennedy J, Astor M. Treatment and outcomes of dogs with hepatocutaneous syndrome or hepatocutaneous-associated hepatopathy. J Vet Intern Med. 2022;36(1):106-115. doi:10.1111/jvim.16323. Open access (CC BY). https://pmc.ncbi.nlm.nih.gov/articles/PMC8783367/
  4. Loftus JP, Center SA, Astor M, et al. Clinical features and amino acid profiles of dogs with hepatocutaneous syndrome or hepatocutaneous-associated hepatopathy. J Vet Intern Med. 2022;36(1):97-105. https://pubmed.ncbi.nlm.nih.gov/34477245/
  5. DeMarle KB, Webster CRL, Penninck D, Ferrer L. Approach to the Diagnosis of Hepatocutaneous Syndrome in Dogs: A Retrospective Study and Literature Review. J Am Anim Hosp Assoc. 2021;57(1):15-25. https://pubmed.ncbi.nlm.nih.gov/33260213/
  6. Hall-Fonte DL, Center SA, McDonough SP, et al. Hepatocutaneous syndrome in Shih Tzus: 31 cases (1996-2014). J Am Vet Med Assoc. 2016;248(7):802-813. https://pubmed.ncbi.nlm.nih.gov/27003022/
  7. March PA, Hillier A, Weisbrode SE, et al. Superficial necrolytic dermatitis in 11 dogs with a history of phenobarbital administration (1995-2002). J Vet Intern Med. 2004;18(1):65-74. https://pubmed.ncbi.nlm.nih.gov/14765734/