Staph infections in pigs are most commonly caused by the bacterium Staphylococcus hyicus, which produces toxins that attack the skin and cause a condition known as exudative epidermitis, or “greasy pig disease.” It primarily strikes piglets between 5 and 60 days old, and in acute cases death can occur within 3 to 5 days. Treatment combines systemic antibiotics, topical skin care, fluid support, and environmental cleanup to stop the spread.
Recognizing Staph Infection in Pigs
The first signs are listlessness, loss of appetite, and reddening of the skin in one or more piglets in a litter. Small circular ulcerations with a clear, wet discharge typically appear around the face first, often starting at sites where the skin was already broken by scrapes, cuts, or needle teeth injuries. Within hours, the infection spreads down the neck and flanks. Lesions merge together, the exudate turns thick and brown, and the skin takes on a greasy, thickened appearance with coarse hair. Mouth and tongue ulcers can also develop.
Piglets as young as 3 to 4 days old can be affected, especially those born to gilts whose colostrum doesn’t carry enough protective antibodies. Morbidity in a litter can range from 10% to 90%, and most piglets under 6 weeks will die within 10 days if left untreated. Weaned pigs tend to develop a milder, chronic form with crusty lesions and ear-tip necrosis. Mortality is rare in older pigs, but recovery is slow and growth is significantly delayed, often accompanied by diarrhea, dehydration, and wasting.
Ruling Out Other Skin Conditions
Several other conditions can mimic the look of greasy pig disease. Sarcoptic mange, ringworm, swine pox, and pityriasis rosea all cause skin lesions in pigs and need to be considered before starting treatment. Sunburn, photosensitization, insect bites, and nutritional deficiencies (particularly zinc, niacin, or biotin) can also produce dermatitis that overlaps visually with staph. When lesions appear circular and scattered across the body rather than starting at the face and spreading outward, misdiagnosis is especially common. A veterinarian can confirm the staph diagnosis with skin swabs and bacterial culture, which also identifies which antibiotics the particular strain is sensitive to.
Antibiotic Treatment
Systemic antibiotics are the backbone of treatment and should be started as soon as greasy pig disease is suspected. Common injectable options include penicillin G, ampicillin, ceftiofur, lincomycin, and oxytetracycline. These are given by intramuscular injection, typically once daily, with treatment courses running 3 to 5 days depending on the drug and severity.
Getting a culture and sensitivity test done is important, because antibiotic resistance is a growing problem in swine staph. Livestock-associated MRSA (methicillin-resistant Staphylococcus aureus), particularly the ST398 strain, is now found on roughly 70% of pig farms in the Netherlands, and resistance patterns are worsening in operations that rely heavily on certain drug classes like cephalosporins. A sensitivity test tells you exactly which antibiotics will work against the strain on your farm, saving time and reducing unnecessary drug use. Your veterinarian can guide the specific drug choice, dosage, and withdrawal periods for your operation.
Topical Skin Care
Alongside injectable antibiotics, cleaning the skin helps remove the greasy exudate and reduces the bacterial load on the piglet’s body. Gentle washing with a chlorhexidine or iodine-based antiseptic solution loosens the crusts and lets the skin begin to heal. For individual piglets, a soft cloth soaked in warm antiseptic solution works well. In larger outbreaks, dilute antiseptic sprays can be applied across affected litters. Treated skin should be allowed to dry before piglets return to bedding, since damp skin in a dirty environment re-exposes wounds to bacteria almost immediately.
Supportive Care for Affected Piglets
Severely affected piglets lose fluid rapidly through damaged skin and often develop diarrhea on top of that. Dehydration is one of the main reasons young piglets die from this disease. Oral electrolyte solutions should be provided to any piglet showing signs of greasy pig disease. For piglets too weak to drink, subcutaneous fluid administration may be necessary. Keeping affected piglets warm is also critical, since widespread skin damage impairs their ability to regulate body temperature. Ensuring continued access to the sow for nursing, or supplementing with milk replacer, supports caloric intake during recovery. Even with treatment, expect recovery to be slow. Affected pigs often show delayed growth for weeks after the skin heals.
Cleaning the Environment
Staphylococcus hyicus survives well on pen surfaces, and cross-infection explodes when piglets are mixed at weaning, with morbidity reaching up to 80% in some outbreaks. Thorough cleaning and disinfection of farrowing crates, creep areas, and weaning pens is essential to stop the cycle.
Start by removing all organic material: manure, bedding, feed residue, and crusted exudate. Surfaces need to be visibly clean before disinfection, because organic matter inactivates most disinfectants. Wash surfaces with detergent and hot water, then allow them to dry completely. Apply an EPA-registered disinfectant effective against staphylococcal bacteria at the concentration and contact time listed on the label. After disinfection, allow the facility a period of downtime with no animals present. This drying period further reduces bacterial survival through desiccation, which is especially important on porous surfaces like concrete and wood where uniform disinfectant coverage is difficult.
Preventing Future Outbreaks
Since the bacterium enters through broken skin, reducing skin injuries in piglets is one of the most effective prevention strategies. Clipping needle teeth within 24 hours of birth significantly cuts facial injuries among littermates. Research from Virginia Cooperative Extension found that litters with unclipped teeth had 65% more teat and udder injuries on sows by day 7, and piglets in those litters had significantly more facial wounds at both 7 and 21 days. Those facial wounds are exactly the entry points staph exploits. Tail docking should also be done with sterilized instruments to avoid creating another infection route.
Roughened flooring, sharp pen edges, and abrasive concrete are common culprits for skin abrasions on feet and legs. Smoothing these surfaces and maintaining clean, dry bedding removes a major source of skin damage. On farms with recurring problems, ensuring that farrowing areas are fully cleaned and dried between litters breaks the cycle of environmental contamination. Managing gilt integration so that young sows develop immunity before farrowing also helps, since piglets born to gilts with poor colostral antibodies are the most vulnerable. Some farms have had success with autogenous vaccines, where killed bacteria from the farm’s own staph isolate are used to immunize sows before farrowing, boosting the antibody protection passed to piglets through colostrum.
Avoiding unnecessary mixing of litters, maintaining low stocking densities in weaning pens, and keeping humidity under control all reduce transmission pressure. In herds with a history of outbreaks, strategic antibiotic treatment at processing (iron injection, teeth clipping, tail docking) can provide a window of protection during the highest-risk period, though this should be guided by veterinary advice and culture results to avoid contributing to resistance.