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(Epidemic Parotitis)


Brenda L. Tesini

, MD, University of Rochester School of Medicine and Dentistry

Reviewed/Revised May 2023
Topic Resources

Mumps is an acute, contagious, systemic viral disease, usually causing painful enlargement of the salivary glands, most commonly the parotids. Complications may include orchitis, meningoencephalitis, and pancreatitis. Diagnosis is usually clinical; all cases are reported promptly to public health authorities. Treatment is supportive. Vaccination is effective for prevention.

The virus that causes mumps, a paramyxovirus, is spread by droplets or saliva. The virus typically enters through the nose or mouth. It is present in saliva up to 7 days before salivary gland swelling appears, and transmissibility is highest just before the development of parotitis. The virus is also in blood and urine in varying amounts, and, if the central nervous system (CNS) is involved, in cerebrospinal fluid (CSF).

Infection with mumps usually confers permanent immunity.

Mumps is less communicable than measles Measles Measles . It occurs mainly in unimmunized populations, but outbreaks among largely immunized populations have occurred. A combination of primary vaccine failure (failure to develop immunity after vaccination) and waning immunity may have played a part in these outbreaks.

In 2006, there was a resurgence of mumps in the United States with 6584 cases, which occurred primarily in young adults with prior vaccination. Since that time, sporadic outbreaks, mainly at college campuses and in other close-knit communities, have contributed to cases fluctuating from a low of 229 in 2012 to another high of 6369 in 2016. In 2022, 322 cases were reported (see the Centers for Disease Control and Prevention's [CDC] Mumps Cases and Outbreaks).

As with measles, mumps cases may be imported then lead to community transmission. Such spread is especially likely in congregate settings (eg, college campuses) or people in close-knit communities that live in crowded conditions.

Peak incidence of mumps is during late winter and early spring.

Disease can occur at any age but is unusual in children < 2 years, particularly those < 1 year. Approximately 25 to 30% of cases are asymptomatic.

Symptoms and Signs of Mumps

After a 12- to 24-day incubation period, most people develop headache, anorexia, malaise, and a low- to moderate-grade fever. The salivary glands become involved 12 to 24 hours later, with fever up to 39.5 to 40° C. Fever persists for 24 to 72 hours.

Glandular swelling peaks on about the 2nd day and lasts 5 to 7 days. Involved glands are extremely tender during the febrile period.

Parotitis is usually bilateral but may be unilateral, especially at the onset. Pain while chewing or swallowing, especially while swallowing acidic liquids such as vinegar or citrus juice, is its earliest symptom. It later causes swelling beyond the parotid in front of and below the ear.

Occasionally, the submandibular and sublingual glands also swell and, more rarely, are the only glands affected. Submandibular gland involvement causes neck swelling beneath the jaw, and suprasternal edema may develop, perhaps because of lymphatic obstruction by enlarged salivary glands. When sublingual glands are involved, the tongue may swell. The oral duct openings of the affected glands are edematous and slightly inflamed. The skin over the glands may become tense and shiny.

Complications of mumps

Mumps may involve organs other than the salivary glands, particularly in postpubertal patients. Such complications include

  • Orchitis or oophoritis

  • Meningitis or encephalitis

  • Pancreatitis

Approximately 30% of unvaccinated and 6% of vaccinated infected postpubertal males develop orchitis Orchitis Orchitis (testicular inflammation), usually unilateral, with pain, tenderness, edema, erythema, and warmth of the scrotum. Some testicular atrophy may ensue, but testosterone production and fertility are usually preserved.

In females, oophoritis (gonadal involvement) is less commonly recognized, is less painful, and does not impair fertility.

Meningitis Overview of Meningitis , typically with headache, vomiting, stiff neck, and CSF pleocytosis, occurs in 1 to 10% of patients with parotitis. Encephalitis Encephalitis , with drowsiness, seizures, or coma, occurs in approximately 1/1000 cases. About 50% of CNS mumps infections occur without parotitis.

Pancreatitis Overview of Pancreatitis , typically with sudden severe nausea, vomiting, and epigastric pain, may occur toward the end of the first week. These symptoms disappear in about 1 week, leading to complete recovery.

Prostatitis, nephritis, myocarditis, hepatitis, mastitis, polyarthritis, deafness, and lacrimal gland involvement occur extremely rarely.

Inflammation of the thyroid and thymus glands may cause edema and swelling over the sternum, but sternal swelling more often results from submandibular gland involvement with obstruction of lymphatic drainage.

Diagnosis of Mumps

  • History and physical examination

  • Viral detection via reverse transcription–polymerase chain reaction (RT-PCR)

  • Serologic testing

Mumps is suspected in patients with evidence of salivary gland inflammation and typical systemic symptoms, particularly if there is parotitis or a known mumps outbreak. Laboratory testing is usually not needed to make a diagnosis in typical cases but is strongly recommended for public health purposes.

Mumps is also suspected in patients with unexplained aseptic meningitis or encephalitis during mumps outbreaks. Lumbar puncture is necessary for patients with meningeal signs.

Differential diagnosis includes other conditions can cause similar glandular involvement (see table ).


Non-Mumps Causes of Parotid and Other Salivary Gland Enlargement

Suppurative bacterial parotitis

HIV parotitis

Other viral parotitis

Metabolic disorders (eg, uremia, diabetes mellitus)

Mikulicz syndrome (a chronic, usually painless parotid and lacrimal gland swelling of unknown etiology that occurs with tuberculosis, sarcoidosis, systemic lupus erythematosus, leukemia, and lymphosarcoma)

Drug-related parotid enlargement (eg, due to iodides, phenylbutazone, or propylthiouracil)

Laboratory diagnosis of mumps is necessary if disease has features atypical for mumps such as the following:

  • Unilateral

  • Recurrent

  • Occurs in previously immunized patients

  • Causes prominent involvement of tissues other than the salivary glands

  • Parotitis lasting 2 days without an identified cause

RT-PCR is the preferred method of diagnosis; however, serologic testing of acute and convalescent sera by complement fixation or enzyme-linked immunosorbent assays (ELISA) and viral culture of the throat, CSF, and occasionally the urine can be done. In previously immunized populations, IgM testing may be falsely negative; therefore, RT-PCR assays should be done on samples of saliva or throat washings as early in the course of the disease as possible.

Other laboratory tests are generally unnecessary. In undifferentiated aseptic meningitis, an elevated serum amylase level can be a helpful clue in the diagnosis of mumps despite the absence of parotitis. White blood cell count is nonspecific; it may be normal but usually shows slight leukopenia and neutropenia.

In meningitis, CSF glucose is usually normal but is occasionally between 20 and 40 mg/dL (1.1 and 2.2 mmol/L), as in bacterial meningitis. CSF protein is only mildly elevated.

Treatment of Mumps

  • Supportive care

Treatment of mumps and its complications is supportive. The patient is isolated until glandular swelling subsides.

A soft diet reduces pain caused by chewing. Acidic substances (eg, citrus fruit juices) that cause discomfort should be avoided.

Repeated vomiting due to pancreatitis may necessitate IV hydration.

For orchitis, bed rest and support of the scrotum in cotton on an adhesive-tape bridge between the thighs to minimize tension or use of ice packs often relieves pain. Corticosteroids have not been shown to hasten resolution of orchitis.

Prognosis for Mumps

Uncomplicated mumps usually resolves, although, rarely, a relapse occurs after about 2 weeks.

Prognosis for patients with meningitis is usually good, although permanent sequelae, such as unilateral (or rarely bilateral) nerve deafness or facial paralysis, may result.

Postinfectious encephalitis, acute cerebellar ataxia, transverse myelitis, and polyneuritis occur rarely.

Prevention of Mumps

Two doses are recommended:

  • The first dose at age 12 to 15 months

  • The second dose at age 4 to 6 years

Infants immunized at < 1 year of age still require 2 additional doses given after their first birthday.

The vaccine causes mild or inapparent, noncommunicable infection. Fever > 38° C occurs 5 to 12 days after inoculation in 5 to 15% of vaccinees and can be followed by a rash. Central nervous system reactions are exceedingly rare. The MMR vaccine does not cause autism Measles-Mumps-Rubella (MMR) Vaccine Despite the rigorous vaccine safety systems in place in the United States, some parents remain concerned about the safety of the use and schedule of vaccines in children. These concerns have... read more .

MMR is a live vaccine and is contraindicated during pregnancy.

Postexposure vaccination does not protect against mumps from that exposure. Mumps immune globulin is no longer available, and serum immune globulin is not helpful.

The CDC recommends isolation of infected patients with standard and respiratory droplet precautions for 5 days after the onset of parotitis. Susceptible contacts should be vaccinated, and a third dose is recommended for previously immunized people at increased risk of mumps during an outbreak, as determined by public health officials. Robust data are lacking, but a third dose and additional measures may help control an outbreak (3 Prevention references Mumps is an acute, contagious, systemic viral disease, usually causing painful enlargement of the salivary glands, most commonly the parotids. Complications may include orchitis, meningoencephalitis... read more Prevention references ). Nonimmune asymptomatic health care professionals should be excused from work from 12 days after the initial exposure through 25 days after the last exposure.

Prevention references

Key Points

  • Mumps causes painful enlargement of the salivary glands, most commonly the parotids.

  • Cases may occur in vaccinated people because of primary vaccination failure or waning immunity.

  • Approximately 30% of unvaccinated and 6% of vaccinated infected postpubertal males develop orchitis, usually unilateral; some testicular atrophy may occur, but testosterone production and fertility are usually preserved.

  • Other complications include meningoencephalitis and pancreatitis.

  • Laboratory diagnosis is done mainly for public health purposes and when disease manifestations are atypical, such as absence of parotitis, unilateral or recurrent parotitis, parotitis in previously immunized patients, or prominent involvement of tissues other than the salivary glands.

  • Universal vaccination is imperative unless contraindicated (eg, by pregnancy or severe immunosuppression).

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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