Balanoposthitis in dogs – discharge and inflammation

Overview

Preputial discharge and true inflammation

The prepuce is a skin fold protecting the penis beneath a dog's abdomen. Its cavity is lined by a mucous membrane. Balanitis means inflammation of the penile mucosa. Posthitis means inflammation of the preputial mucosa. Both can occur together.

Normal preputial discharge is called smegma. It contains material including shed surface cells and accumulated fluids. A small amount of discharge alone usually causes no noticeable signs. True inflammation involves mucosal changes such as redness and tenderness. Ordinary smegma does not need antibiotics.

A small amount of discharge can also look yellowish or greyish. Colour is therefore assessed alongside the amount, mucosal changes and the dog's signs.

Causes

Local irritation and underlying diseases

Normal preputial bacteria can overgrow and contribute to inflammation. Penile injury or a foreign body in the prepuce may be involved. A grass awn, for example, can migrate beneath the mucosa. A penile or preputial tumour can also sustain inflammation.

Urinary tract infection and urinary stones are possible underlying causes. In some dogs, a concurrent problem is prostate disease or atopic dermatitis. Self-injury associated with itching can inflame the mucosa.

Bloody discharge can also come from urethral inflammation or prolapse. A blood clotting disorder is another possibility. Investigation therefore locates whether bleeding comes from the preputial lining or elsewhere in the urinary tract.

Sex hormones also affect discharge: androgens increase sebaceous secretion. Flushing or antibiotics do not alter the secretory glands' function. Cleaning aimed only at excessive discharge may therefore have a temporary effect.

Narrowing or inflammation without a clear cause

In phimosis, the preputial opening is too narrow to expose the penis. Urine accumulating inside can then sustain inflammation. Inflammation can also be primary, without another identified disease. This form of unknown cause is called idiopathic.

Risk factors

Mucosal inflammation occurs particularly in unneutered males. No general breed predisposition has been demonstrated. A preputial anatomical abnormality can predispose to problems. Penile injury and foreign bodies are other local risk factors.

A 2018 Rhodesian Ridgeback health survey from northern Europe recorded 27 reports of penile or preputial inflammation. This was an owner survey of one breed, rather than the risk of disease in all male dogs. Discharge around the prepuce can stick to long hair and make cleaning difficult. A narrow prepuce may be congenital or develop later after injury and inflammation.

Impaired immune defences can also predispose to inflammation of the preputial lining. Bacteria normally present may then cause infection when defences weaken.

Typical symptoms

Excessive discharge and persistent attention to the area are particularly noticeable. At home, you may see:

• More discharge than usual from the preputial opening.
• Discharge also accumulating on hindlimb hair.
• Repeated, prolonged preputial licking.
• Thick, yellowish or greenish discharge.
• Unpleasant-smelling discharge or blood.
• Redness or tenderness in the area.

Marked painful swelling is uncommon in ordinary balanoposthitis. It is more often associated with injury or a foreign body, for example. Difficulty urinating changes the urgency even if discharge was the first thing noticed.

Complications and consequences

Persistent irritation and narrowing

Inflamed mucosa is more readily damaged by continuous licking. With persistent inflammation, the surface may thicken and become nodular through lymphoid tissue overgrowth. Severe untreated inflammation can scar and narrow the preputial opening.

Adhesions may form between the penis and prepuce. These can hinder exposure of the penis and make mating painful. Severe cases may develop an abscess around the prepuce or glans. Many mild or moderate cases settle with local care. The problem can nevertheless recur.

If the penis is trapped outside the prepuce, the opening's rim can instead compromise blood flow. This is the separate condition paraphimosis, which may require surgery if it progresses. It differs from a normally protected penis with discharge as the only finding.

Diagnosis at the vet

Examination locates the discharge source

Your vet examines the penis and entire preputial cavity to its deepest recess. Sedation or anaesthesia may be needed. Small mucosal tracts can reveal an otherwise hidden foreign body. Ultrasound can help find a foreign body tract, haematoma or mass.

An endoscope can be used, but an otoscope can also help inspect the preputial cavity's inner surface.

Cytology and bacterial culture

A discharge cell sample is assessed for inflammatory cells and bacteria. Degenerate neutrophils containing bacteria support suspicion of bacterial infection. Culture interpretation is complicated by normal bacteria in the prepuce. An unusual species or dominant growth of one species can suggest a disturbed microbial balance.

In a study of 20 males, discharge was found at 15 of 40 reproductive examinations. Bacterial counts did not differ significantly between dogs with and without discharge. This illustrates why bacterial numbers alone are not interpreted as a diagnosis of inflammation.

Even physiological discharge can contain numerous neutrophils, white blood cells involved in inflammatory responses. It typically contains few bacteria, however, and no intracellular bacteria. Cytology therefore distinguishes bacteria free in the sample from bacteria inside immune cells. Preputial bacteria may include E. coli, staphylococci and streptococci.

Mycoplasmas were also found in males without inflammatory penile changes. Their detection therefore does not automatically mean a disease requiring medication.

Other tests according to signs

An abnormal mucosal lesion can be sampled for cytology or biopsy. Investigation of bloody discharge may include a blood count, urinalysis and urine culture. The prostate is examined where needed. Itchy skin or other neurological signs may instead direct investigation towards skin disease or a neurological cause.

General examination assesses breathing, body temperature and circulation. Reproductive examination can also include palpation of the testes and epididymides. These are assessed for size, symmetry, warmth and pain, among other features. Material for bacterial testing follows the suspected inflammation site: options include preputial discharge, semen and a tissue sample.

X-rays may be needed for a suspected penile bone fracture. Examination of a breeding male may extend to semen assessment when reduced fertility is also a problem.

Treatment

Local care and addressing the cause

Your vet chooses treatment according to the cause and severity of inflammation. Care includes cleaning and flushing the preputial cavity with a suitable mild antiseptic or sterile saline solution. Flushing mechanically removes accumulated discharge and debris. It also reduces the local bacterial load.

Long hair around the opening may be trimmed to make cleaning easier. A collar prevents intense licking during treatment. An NSAID may be needed to control pain and inflammation. Any abscess is opened by a vet.

When are antibiotics or surgery needed?

A topical antibiotic may be considered for severe inflammation when culture confirms infection. A systemic antibiotic, acting throughout the body, is rarely necessary. In severe, recurrent or poorly responsive cases, culture and susceptibility testing guide medicine selection. Unnecessary antibiotic use favours resistant bacterial strains.

If inflammation involves preputial narrowing that obstructs urination, the opening can be enlarged surgically. Neutering can reduce genital discharge but may not stop it.

Safety of local treatment

A treatment product can also irritate mucosa: in one flushing study, 5 of 20 dogs developed mild penile and preputial redness after repeated iodine-based treatment. This was a finding from a particular treatment, rather than an adverse effect rate for every flush. Product suitability for mucosa and veterinary instructions determine how local care is carried out.

Prevention

Keeping the preputial opening tidy can help remove discharge accumulating in long hair. Preventing intense licking reduces ongoing mucosal damage. Identified structural and other predisposing problems are treated to reduce recurrent irritation.

Medical benefit and long-term effects of regular preventive preputial flushing in a dog without signs have not been established. An immediate reduction in bacterial counts after flushing therefore does not show that a healthy dog will avoid inflammation. Ordinary smegma does not need attempted removal with antibiotics.

Flushing does not make the preputial lining permanently bacteria-free. In a small follow-up of 4 Beagles, bacterial species numbers varied and no consistent trend remained at 14 days. This describes variation in bacteria, rather than a time to repeat flushing.

Important for dog owners

What should you monitor at home?

Record when discharge began, whether it has increased and how much your dog licks. Bring details of similar previous episodes, current medication and skin signs. The history includes previous illnesses and medicines used. Recurrence patterns help investigate problems involving licking and penile exposure.

If discharge is bloody, note whether it accompanies urination or also appears at rest. With prostate disease, bloody fluid may drip from the prepuce independently of urination. Ask whether flushing is needed, which solution suits your dog and how to use it before home care. Also agree which changes require another examination. Treatment addresses an identified predisposing disease as well; reducing discharge alone does not resolve every underlying cause.

Frequently asked questions

Does a small amount of preputial discharge always mean inflammation?

No. Many sexually mature males have a little mucoid discharge without other noticeable significant disease. Mucosal irritation and pain suggest true inflammation. Excessive discharge and persistent licking are also reasons for examination.

Does my dog always need an antibiotic?

Ordinary smegma does not need antibiotics. Treatment of a local bacterial infection follows findings and culture where necessary. A systemic antibiotic is rarely needed. Visible discharge alone is therefore not an automatic reason to start medication.

Does neutering eliminate preputial discharge?

Neutering can reduce genital discharge, but discharge may continue afterwards. An underlying foreign body, structural abnormality or another disease also needs its own treatment. The need for neutering is decided with your vet according to the dog's overall situation.

Can the prepuce be flushed just in case?

Medical benefit or long-term effects of preventive flushing in a dog without signs have not been established. In inflammation, however, flushing may form part of local care selected by your vet. Home treatment requires individual veterinary instructions for the particular solution and technique.

What if the penis remains outside the prepuce?

A penis trapped outside the prepuce is paraphimosis and requires urgent care. Exposed tissue can rapidly swell, dry out and become painful. This differs from a small amount of discharge at the opening, so contact an emergency vet immediately.