What is scrofula and how common is it?

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Scrofula is a form of TB that occurs outside of the lungs. It occurs when TB bacteria travel through the bloodstream to other parts of the body, particularly the lymph nodes in the neck. It is also called tuberculous lymphadenitis (TBLA).

Scrofula is usually painless but causes swelling in the neck that can last for weeks or months.

Doctors are not always sure where an individual becomes exposed to the bacteria that causes scrofula. One likely cause is environmental exposure through contaminated water.

Scrofula does not respond to antibiotics, which is one factor that can help a doctor diagnose it. A doctor may also perform a small biopsy of the swollen lymph nodes to check for the bacteria that cause scrofula.

Read more about lymph nodes.

The prevalence of scrofula varies widely between developed and developing countries.

In the United States in 2021, there were 7,882 reported cases of TB. Scrofula accounts for about 20% of those cases. It is more common among females than males and in people ages 30–40 years.

Swelling and inflammation on one side of the neck are the hallmarks of scrofula. One or more masses develop that are usually painless and slow growing.

Masses should not feel tender and may become firmer over time. They may ulcerate and drain fluid. The average mass measures 3 centimeters (cm), but masses may be as large as 8–10 cm.

The following symptoms may appear around 4–8 weeks before the appearance of neck swelling:

• fever
• chills
• night sweats
• unexplained weight loss
• failure to thrive in infants

The bacterium Mycobacterium tuberculosis causes over 95% of scrofula cases. Nontubercular mycobacteria types, such as Mycobacterium scrofulaceum, cause the remaining 5%.

Scrofula, or TBLA, may occur due to the reactivation of latent TB infection.

A 2019 Danish study explored the reasons underlying the high incidence of TBLA among immigrants to Denmark and the relatively low incidence among Danish nationals. Many immigrants were from countries with high rates of TB and reported previous experience with TB. The study’s authors suggested that TBLA was due to the reactivation of latent TB infection.

Read about the different types of TB.

A doctor will perform a physical examination and several tests to diagnose scrofula. The condition is difficult to diagnose, as it is rare and can mimic other conditions.

Fine needle aspiration involves using a thin needle to remove some of the fluid in the mass on the neck. The doctor sends the fluid to a lab for testing, where scientists look for the presence of mycobacteria and other indicators of scrofula.

The doctor may order X-rays, ultrasounds, or other imaging of the lungs, neck, or other areas to check for signs of TB.

They may also order a tuberculin skin test to check for exposure to TB. A healthcare professional injects a small amount of tuberculin-purified protein derivative (PPD) just beneath the skin’s surface. The doctor must check the area for results 48–72 hours later.

In adults, scrofula treatment requires taking multiple medications over several months.

A doctor will prescribe the following medications for the first 2 months:

• isoniazid
• rifampicin
• ethambutol
• pyrazinamide

For the following 4 months, doctors prescribe continued treatment with rifampicin and isoniazid.

Doctors may recommend surgery to remove the affected lymph nodes in healthy individuals if medication does not clear up the inflammation.

Surgery is not always suitable, however, due to a high rate of recurrence and the possibility of creating a deeper wound called a fistula.

Scrofula can develop from a latent TB infection or exposure to active bacteria. Some people are at greater risk of developing TB infections in the lungs or other areas of the body. These include:

• people living with HIV
• those who have contracted TB in the previous 2 years
• babies and young children
• people who use intravenous drugs
• people with weakened immune systems
• older adults
• anyone not adequately treated for previous TB

TB spreads through the air. People should avoid spending time in close contact with anyone known to have the condition, particularly when traveling to countries with a high incidence of TB.

The Bacille Calmette-Guerin (BCG) vaccine provides some protection against TB, but doctors in the United States rarely recommend it.

Read more about the BCG vaccine.

Scrofula can sometimes spread beyond the neck to other parts of the body. The enlarged lymph node or nodes can form an open wound and begin draining. This provides an entry point for other bacteria and infections. The same thing can occur when surgeons remove the mass.

Rarely, after a biopsy, an individual may feel some pain or a tunnel may develop underneath the mass. This is called a sinus tract. Scarring can also occur.

Scrofula is rare, and doctors can mistake it for other conditions, so diagnosis may take a long time. This increases the risk of complications.

Scrofula is more severe in children under the age of 5 years, and people with weakened immune systems may need drug therapy for longer.

After treatment, up to 100% of people with scrofula caused by Mycobacterium tuberculosis recover. The recovery rate for scrofula caused by non-tuberculous mycobacterium is over 90% following surgery.

Scrofula is a form of TB infection that occurs outside of the lungs. The main symptom is inflamed lymph nodes in the neck, causing the neck to swell on one side.

Scrofula is usually painless but may cause other symptoms, such as fever, night sweats, or chills. It can ulcerate, causing an open wound that is vulnerable to infection.

Treatment for scrofula involves taking multiple medications over 6 months and, in some cases, undergoing surgery.