1. General Considerations

   1. Exudative epidermitis or greasy pig disease is typically a disease of suckling or newly weaned pigs.
   2. Affected piglets may die of anorexia and dehydration a few days after the infection.
   3. More than one piglet is typically affected in a farm and the disease can be a significant cause of mortality and poor growth rate.

1. 4. The disease has a worldwide distribution.

2. Etiology

   1. Staphylococcus hyicus subsp. hyicus is by far the most common agent; however, other staphylococci capable of producing exfoliative toxins including S. sciuri, S. chromogenes and S. aureus have been rarely isolated from skin lesions.

3. Clinical Signs

   1. Clinically, the disease is divided into peracute, acute and subacute forms.
      1. Peracute:
         1. Initially, a dark-brown “waxy” crust develops periocularly, and then a vesicopustular eruption develops on the nose, lips, tongue, gums, and coronets.
         2. The disease progresses to affect the entire body with lesions characterized by erythema, a moist to greasy exudate and brown crusts.
         3. The feet often presents erosions of the coronary band and heel.
         4. The piglets show progressive depression, anorexia, and polydipsia and usually die within 3 to 5 days.
         5. Internal organs may also be affected.

1. 2. Acute:
      1. The clinical presentation is similar to the peracute form but the skin becomes thicker and wrinkled in the acute form.
      2. Death typically occurs within 4 to 8 days.
   3. Subacute:
      1. Skin lesions are milder and typically limited to the head and ears and are less exudative.
      2. The piglets are generally healthy otherwise and the disease resolves spontaneously.

4. Diagnosis

   1. History and characteristic clinical signs.
   2. Differential diagnoses include sarcoptic mange, dermatophytosis, pityriasis rosea, zinc deficiency, swine pox and biotin deficiency.
   3. Cytology of exudative lesions shows coccoid-shaped bacteria.
   4. Biopsy should be performed to confirm a presumptive clinical diagnosis and to rule other diseases. It shows subcorneal vesicular-to-pustular dermatitis and acantholytic keratinocytes.
   5. Culture from vesicles or pustules and conjunctiva yields S. hyicus and, less frequently, the other staphylococci species mentioned above.

5. Treatment and Prognosis

   1. The worse the clinical condition the smaller the chances of response to treatment.
   2. Ideally, antibiotic therapy should be based on culture and sensitivity results as resistant strains of S. hyicus have been reported.
   3. Penicillin (5000 IU/Kg twice daily) given IM for 3 to 5 days has been effective.
   4. Tylosin (8 mg/kg) given IM for 2 to 3 days has also been reported to be beneficial.
   5. Good results have been seen with one injection of oxytetracycline (11 to 18 mg/kg) followed by oxytetracycline in the feed (300g/Ton).
   6. Good hygiene and management practices should be instituted to prevent infection.
   7. Immunization has been reported to be effective in the prevention of experimentally induced exudative epidermitis.
   8. The peracute and acute forms of the disease are severe and often result in death. In contrast, the subacute form typically spontaneously resolves.

References

Foster AP. Staphyloccal skin disease in livestock. Vet Dermatol 2012; 23:342-352.

Lua L, Hea K, Nia Y et al. Exudative epidermitis of piglets caused by non-toxigenic Staphylococcus sciuri. Vet Microbiol 2017; 199:79-84.

Mebus CA, Underdahl NR, Twiehaus, MJ. Exudative epidermitis: pathogenesis and pathology. Vet Pathol 1968; 5: 146-163.

Scott DW. Bacterial Diseases. In: Large Animal Dermatology. Philadelphia, PA: W.B. Saunders, 1988; 123-126.

Wegener HC, Skov-Jensen EW. Exudative epidermatitis. In: Straw BE, Zimmerman JJ, D’Allaire S et al., eds. Diseases of Swine, 9th edn. Ames, IA: Blackwell Publishing, 2006; 675-679.