Diseases of the skin

Question 1

Inherited skin diseases of pigs

Answer 1

Epitheliogenesis imperfecta

Hypotrichosis

Dermatosis vegetans

Congental porphyria

Pityriasis rosea

Question 2

Parasitic skin diseases of pigs

Answer 2

Lice

Sarcoptic mange

Demodectic mange

Fly worry

Question 3

Viral skin diseases of pigs

Answer 3

Pig pox

Foot and mouth disease*

Swine vesicular disease*

Seneca Valley Virus

Classical swine fever*

PDNS

Question 4

Bacterial skin diseases of pigs

Answer 4

Septicaemias

Ear necrosis

Greasy pig disease

Question 5

Fungal skin diseases of pigs

Answer 5

Ringworm

Question 6

Nutritional skin diseases of pigs

Answer 6

Vitamin A deficiency

Vitamin B definciency

Zn parakeratosis

Question 7

Toxic skin diseases of pigs

Answer 7

Selenium toxicity

Mycotoxin (ergot)

Photosensitisation

Question 8

Physical skin diseases of pigs

Answer 8

Tail / ear biting

Fighting

Sunburn / heat stroke

Burns

Electrocution

Aural haematoma

Pressure injury

Question 9

Epitheliogenesis imperfecta

Answer 9

Large White & Saddleback breeds.

autosomal recessive gene.

Piglet born with an area of skin - especially on the flank - missing.

Treatment: Self resolution, or if severe euthanasia.

Question 10

Hypotrichosis - hairless piglets

Answer 10

Autosomal dominant gene

Occasionally also caused by Iodine deficiency.

One or more piglets in litter born with no hair or very little hair.

Treatment: None. May have to euthanase very weak piglets.

Question 11

Louse infestation

Answer 11

now uncommon in commercial production

Haematopinus suis.

brown dorsoventrally flattened sucking louse

Life cycle complete in 30 days.

The pig is the only host.

Lice can survive for 3 days away from pig.

Lice can transmit pig pox and Eperythrozoon (Mycoplasma) suis.

Heavy infestation causes skin irritation, rubbing, hair loss, weight loss and occasionally anaemia.

Treatment: Avermectin based products typically used. These include Doramectin and , Ivermectin

Question 12

Pityriasis rosea

Answer 12

Quite common on many farms. Usually only one or two pigs in group are affected but occasionally larger numbers.

Autosomal dominant trait with incomplete penetrance; boar dependent

Mostly seen in individual pigs aged 2 - 16 weeks.

Outbreaks affect 2/3 pigs/litter around weaning period over a 2-3 month period.

Skin lesions (pustular dermatitis) seen chiefly on ventral surface of the abdomen and the medial aspect of the thighs.

Lesions are initially small red nodules which develop into larger raised plaques with thin crusty covering.

Lesions expand centrifugally leaving normal skin within the irregularly circular lesions.

Usually no systemic signs.

Looks very like ringworm. No fungal hyphae seen

Treatment: None. Emollient cream may speed spontaneous resolution. Complete recovery within 6 weeks is usually seen.

Question 13

Sarcoptic mange

Answer 13

Sarcoptes scabei var suis, a small (0.5 mm) burrowing mite

Mites live on the pig and burrow into the skin where they may produce an allergic reaction.

Spread is mainly by direct pig to pig contact.

Skin is thickened and there is a proliferation of underlying connective tissue.
The head, flank and legs are all affected.
The skin is dry and crusty and pruritis continues and may cause reduction in appetite and growth rates.
Hair loss may follow rubbing and chronic head shaking can cause the development of aural haematomas.

Treatment: avermectins (treat whole herd to eradicate and deep clean buildings two weeks in

Question 14

Demodectic mange

Answer 14

Rare.

Small (3 mm) nodules and pustules may be seen on the skin.

Abscesses may develop later.

Mites (D. phylloides) found in purulent material.

Controlled as part of sarcoptic mange control plan.

Question 15

Fly worry

Answer 15

Stomoxys calcitrans

Blow fly strike can occur but is less common than in sheep. Very sick pigs with wounds and open abscesses may be at risk from strike.

Impact:
* May disturb sows and piglets and reduce suckling.
* Downgrading of carcases at slaughter (bite lesion hypersensitivity).
* Fomite in pig dense areas: PRRSV, PEDV, ASFV.

Treatment - clean up and treat original lesion. Local application of a fly spray or deltamethrin may help prevent re - infestation.

Question 16

Pig pox

Answer 16

Suipox virus from the Poxviridae family.

Direct pig to pig spread but also transmitted by lice and flies.

Skin lesions seen on the face, flanks and belly of affected pigs.

Small (1cm) papules develop with vesicles which rupture to produce dark red scabs.

A congenital form of pig pox has been reported - piglets born with pox lesions sometimes from a clinically unaffected sow.

A high mortality is seen in congenital cases.

In young pigs a conjunctivitis and keratitis may be seen.

No specific treatment. Antibiotics for conjunctivitis may help avoid secondary infection. Topical liquid paraffin may help skin condition improve.

Question 17

Skin lesions of classical swine fever

Answer 17

patchy purple discolouration of the abdominal skin. Cyanotic necrosis of the ear tips also seen.

Question 18

Skin lesions of
Porcine Dermatitis & Nephropathy Syndrome (PDNS)

Answer 18

extensive dermatitis may be seen over the chest, abdomen, thighs and forelegs.

Affected areas show numerous and coalescing purple - red papules and macules of varying size and shape.

Question 19

Skin lesions of Swine Vesicular Disease (notifiable

Answer 19

vesicles seen on the skin of the coronary band. Vesicles and ulcerated areas also seen on the snout, lips and tongue.

Question 20

Skin lesions of Foot & Mouth Disease (notifiable)

Answer 20

vesicles on the coronary band, tongue and snout.

Question 21

Skin lesions of Seneca Valley Virus A (SVV)

Answer 21

a non-notifiable but emerging cause of vesicular disease.

No significant disease, aside from transient lameness and transient mortality in neonates.

Needs to be differentiated from notifiable diseases.

Question 22

Skin lesions in swine erysipelas

Answer 22

Skin lesions are an important sign of this disease.

In peracute erysipelas may see a generalised purple discolouration of the skin.
Other signs include severe depression, pyrexia and sudden death.

In acute erysipelas red, diamond shaped elevated skin lesions are seen and palpable especially over the shoulders and back.

As the lesions get older they become darker and in rare cases sloughing of large areas of the skin of the back occur

Question 23

Skin lesions of Salmonellosis in pigs

Answer 23

Salmonella cholerae suis is probably the most important serotype associated with skin lesions.

Skin lesions including purple cyanotic discolouration and necrosis of the ears are seen.

Purple discolouration also seen on the flanks, behind the elbows and on the caudal aspect of the thighs.

These are signs of septicaemia and may also be seen in cases of severe mastitis caused by Klebsiella spp

Question 24

Ear tip necrosis

Answer 24

may be found in pigs affected by septicaemia

Damage to the tips of the ears of healthy growing pig as a result of bacterial infection

Staph hyicus – the cause of Greasy Pig Disease – is the most common isolate

primary cause of the problem is damage to the tip of the ear either from fighting, knocking on feeders or abrasion

Over-stocking is a key risk factor, as is a failure to properly de-grease

earliest lesions are normally visible on the tips of the ears of pigs at 6-7 weeks old and are usually no more that a black greasy deposit, ear tip slowly erodes

At some point, usually above 14 weeks of age, the erosion will halt and the eroded surface will heal over

Individual cases may often not warrant treatment

antimicrobials to which the causative bacteria is shown to be sensitive and which penetrate well into the skin (such as Lincomycin or Florfenicol) can be effective. Reduction in stocking rates is effective.

Question 25

Greasy pig disease

Answer 25

common

Staphylococcus hyicus. This organism has virulent and non – virulent strains. Dermatophilus spp may be involved in some cases.

Mostly seen in pigs < 6 weeks of age and especially < 2 weeks. Infection is carried by the sow or gilt on her skin or within her vagina

Sudden onset of facial skin lesions with suppressed suckling in affected piglets.
The skin is initially reddened and then becomes thickened and covered with a greasy brown exudate that spreads over the body. The lesions are non - pruritic. Infection occasionally spreads to the mouth and tongue.

Secondary infection with other bacteria may also affect the skin.

Death may occur in untreated piglets.

Treatment: Parenteral penicillin or ampicillin can be effective unless piglets are moribund in which case euthanasia

Washes with chlorhexidine can also be used.

Question 26

Ringworm

Answer 26

uncommon.

Zoonotic

Mostly Trichophyton mentagrophytes. T. verrucosum and M. canis seen occasionally.

Spread by pig to pig contact

Round or ovoid lesions are seen on the shoulders, back and flanks. Lesions are light brown in colour and the skin may be flaky.

Treatment: Topical enilconazole

Question 27

Vitamin A deficiency

Answer 27

Skin lesions are a relatively minor sign of this condition.

The coat is dry and has a ‘shaggy’ appearance with splits at the end of the bristles.

A non specific seborrhoeic dermatitis is sometimes seen.

More serious signs of Vitamin A deficiency include CNS lesions - posterior paralysis, night blindness and congenital defects.

Not all are Vit A responsive.

Food should contain 3 - 9 million IU / tonne. Serum 25 - 60 g/dl.

Question 28

Riboflavin (vit B2 deficiency)

Answer 28

skin lesions include a roughened skin and matting of the hairs by a heavy sebaceous exudate.

May resemble Greasy pig disease

May also see poor growth, limb and eye abnormalities, scouring and irregularities of the oestrous cycle in sows.

Question 29

Nicotinic acid (vit B3) deficiency

Answer 29

can occur in pigs fed on high levels of maize.

The skin may be yellow in colour and show alopecia or irregular hair growth.

At post mortem lesions similar to necrotic enteritis may be seen.

Question 30

Pantothenic acid (vit B5) deficiency

Answer 30

risk of low levels if fat content of food is high or when Copper supplementation used.

Skin lesions include dermatitis, patchy alopecia and a dark exudate around the eyes.

Additional signs include goose stepping gait and diarrhoea.

Demyelination - especially of the peroneal nerve - is seen at PM.

Treatment is by including 10 - 12g Calcium pantothenate per tonne of food.

Question 31

Biotin (Vit B7) deficiency

Answer 31

the diet should include 180 mg biotin per tonne of food.

Levels may fall in diets with high wheat or barley content.

Skin lesions include alopecia, broken hairs, brown crusty lesions and petechial haemorrhages.

May also see signs of lameness caused by cracks in the solar horn which readily become infected.

The response to biotin therapy is often very slow.

Question 32

Parakeratosis

Answer 32

Zn deficiency in diet or malabsorption of Zn from gut in animals with diarrhoea

High levels of soya and bran and also high levels of Ca++ in the diet can predispose.

Signs seen especially in 7 - 10 week piglets

Less likely in outdoor pigs

Poor growth and weight loss.
May see poor herd fertility and breeding results.
Skin lesions - symmetrical erythema with crusty lesions on the flank, back, belly and ears.
Deep fissures are seen between areas of hyper - keratinisation. There is no greasiness and no pruritis.
Some secondary abscessation of the skin may be seen.

Treatment: 200g Zinc Carbonate or sulphate per tonne of food.

Question 33

Tail biting, ear biting

Answer 33

Mainly the result of environmental stress through poor husbandry and inadequate accommodation and nutrition

Severe damage can occur rapidly - the whole tail can be removed and deeper biting damage into the perineal tissues can occur.

Infection can enter the damaged tail and spread upwards through local invasion or by haematogenous means.

Vertebral body abscesses are a common sequel and can result in posterior ataxia or paresis.

Minor injuries are left untreated
Infection should be treated with parenteral and local antibiotics.
Identify and if possible remove individuals who start the biting cycle.

Question 34

Tail docking

Answer 34

has some benefits in reducing the incidence of the problem of tail biting (Welfare (Farmed Animal) Regulations require docking to be done only where managemental correction has not resolved the problem. Docking must be done before 7d of age otherwise anaesthesia is required.

Question 35

FIghting injuries

Answer 35

severe problem in pigs who naturally fight when mixed with animals from another group

Minor lacerations usually heal by primary intention.
Deep wounds must be sutured under sedation and local anaesthetic.
Infected wounds must be cleaned with antiseptic solutions such as chlorhexidine.
Abscesses must be opened and checked to make sure that premature closure and re - formation of further abscesses does not occur.
Antibiotic cover and tetanus antitoxin must be used when necessary.

If groups have to be mixed sedation of all the pigs involved with azaperone before mixing may help but results can be disappointing.

Question 36

Heat stroke

Answer 36

The pig is very susceptible to overheating- perspiration minimal and thick layer of s/c fat insulates the body

progressive distress. Panting - open mouthed gasping respiration. T > 42 C. Membranes may become cyanotic. Tachycardia. Death follows.

cool pig immediately - cold water hosing - increase ventilation.

Question 37

Electrocution

Answer 37

Usually the result of an electrical fault such as poor wiring.

Pigs involved are usually found dead.

Superficial burn marks may be found on the skin.

Signs of a violent death are present.

Fractures of bone especially of the neck of the scapulae or the humerus are common - caused by violent incoordinated muscle contraction.

Blood stained froth may appear at the nose and premature decomposition may occur.

Must treat suspected cases with care in terms of electrical safety and also check that there is no infectious cause of sudden death such as anthrax.

Question 38

Ergot poisoning

Answer 38

An uncommon condition.

Pigs may occasionaly gain access to ergot from contaminated grain or at pasture.

Skin lesions - gangrene of the extremities.

May also see high levels of stillbirth, agalactia and abnormalities of the oestrous cycle.

Treatment of gangrenous extremities - may require surgical aid, local antibiotic therapy or euthanasia.