A buffalo hump is a buildup of fat at the base of the back of your neck, between the shoulder blades. It has several possible causes, ranging from excess body weight to hormonal imbalances, certain medications, and rare genetic conditions. Understanding the cause matters because treatment depends entirely on what’s driving the fat accumulation.
What a Buffalo Hump Actually Is
The medical term is a dorsocervical fat pad. It’s a collection of fat tissue, not a bone or spinal problem, though it can be easy to confuse with one. The fat in a buffalo hump is harder and denser than typical body fat, which is why many people assume they’re feeling their spine when they touch it. This is an important distinction from a “dowager’s hump,” which is an outward curvature of the upper spine (kyphosis) caused by skeletal changes, often from osteoporosis. Both can look similar from the outside, but they have completely different causes and treatments.
Obesity Is the Most Common Cause
The single most frequent reason people develop a buffalo hump is carrying excess body weight. In a study of patients presenting with obesity, 72% had dorsocervical fat accumulation. That’s a striking number, and it highlights that this fat deposit is extremely common in people with generalized obesity, even when no hormonal disorder is present.
This creates a diagnostic challenge. Many of the signs associated with hormonal conditions, like a round face, stretch marks, and a buffalo hump, also show up in people who are simply overweight. In the same study, these features appeared in a major proportion of obese patients who turned out to have perfectly normal cortisol levels. So if you notice a hump forming and you’re also carrying extra weight, the explanation may be straightforward, though it’s still worth investigating further.
Cushing’s Syndrome and High Cortisol
Cushing’s syndrome is the hormonal condition most closely linked to buffalo hump. It happens when your body is exposed to high levels of cortisol over a long period. Cortisol is a stress hormone, but it also plays a powerful role in where your body stores fat.
Here’s how it works: elevated cortisol ramps up the activity of an enzyme that pulls fat from your bloodstream into fat cells. At the same time, it boosts the production of new fat within those cells. Cortisol does this more aggressively in certain fat deposits, particularly around the abdomen, upper back, and face, while fat in the arms and legs may actually shrink. The result is a distinctive pattern of central fat accumulation, with a round face, thickened midsection, and fat buildup at the base of the neck.
Cushing’s syndrome can be caused by a tumor on the pituitary gland or adrenal glands, or it can develop from taking corticosteroid medications (more on that below). If your doctor suspects Cushing’s, screening typically involves a combination of tests: a urine collection measuring cortisol over 24 hours, a saliva sample taken late at night, or a test that checks whether a low dose of a synthetic steroid suppresses your cortisol production the way it should. Because cortisol output varies significantly from day to day, these tests are usually repeated at least twice before drawing conclusions.
Long-Term Steroid Medications
Taking corticosteroid drugs like prednisone for extended periods is one of the most common causes of Cushing’s-like symptoms, including a buffalo hump. These medications are prescribed for conditions like autoimmune diseases, severe asthma, and organ transplant management. They work by mimicking cortisol, which means they trigger the same fat redistribution patterns that naturally elevated cortisol does.
The hump typically develops with high doses taken over weeks to months. In documented cases, patients on high-dose prednisone developed prominent fat deposits along with a rounded face. The fat redistribution generally reverses once the medication is tapered down or stopped, though this process can take months. If you’re on long-term steroids and notice these changes, your doctor can sometimes adjust the dose or switch to a different formulation to reduce side effects.
HIV Treatment and Lipodystrophy
People living with HIV who take antiretroviral therapy can develop a pattern of fat redistribution called lipodystrophy. Two classes of drugs are primarily involved. Protease inhibitors are associated with increased fat around the abdomen and upper back. Nucleoside reverse transcriptase inhibitors contribute to fat loss in the face, arms, and legs. When both drug classes are used together, which is common in standard treatment regimens, the combined effect can be pronounced: fat accumulates in the trunk and neck while the limbs become visibly thinner.
This is a well-recognized and common complication of modern HIV treatment. It doesn’t affect everyone on these medications, and newer drug formulations have reduced the risk somewhat. But for those who do develop it, the changes can be distressing and difficult to reverse even with medication adjustments.
Madelung’s Disease
A much rarer cause is Madelung’s disease, a condition in which symmetrical fatty tumors (lipomas) develop around the neck, shoulders, and upper back. It predominantly affects men between ages 30 and 70, and roughly 90% of diagnosed patients have alcohol-related liver disease. The condition is more common in Mediterranean and European populations.
The underlying problem appears to be a breakdown in the body’s fat metabolism. Normally, hormones like adrenaline signal fat cells to release stored energy. In Madelung’s disease, that signaling pathway doesn’t work properly, so fat accumulates in areas where it shouldn’t. Chronic alcohol use worsens the problem by damaging the energy-producing machinery inside cells and further disrupting fat breakdown. The fatty deposits themselves are painless, but as they grow they can press on surrounding structures, causing difficulty swallowing, speaking, or breathing. Peripheral nerve damage in the arms and legs often develops as well, especially with age.
How to Tell the Cause Apart
Because so many conditions can produce a buffalo hump, figuring out the underlying cause requires looking at the full picture. A few distinguishing features can help narrow things down:
- Obesity alone tends to cause fat accumulation all over, not just at the neck. If you’re generally overweight and don’t have other unusual symptoms, this is the most likely explanation.
- Cushing’s syndrome produces a cluster of signs: the hump plus a round face, thin skin that bruises easily, wide purple stretch marks, muscle weakness, and sometimes high blood sugar. If several of these appear together, cortisol testing is warranted.
- Steroid use is the easiest to identify because you already know you’re taking the medication. The timeline between starting high-dose steroids and noticing fat changes is usually weeks to months.
- HIV lipodystrophy has a characteristic pattern where fat grows in the trunk while shrinking in the limbs and face.
- Madelung’s disease produces symmetrical, distinct fatty masses rather than a single diffuse hump, and is strongly associated with heavy alcohol use.
Reducing a Buffalo Hump
Treatment depends entirely on what’s causing the fat buildup. If the cause is a medication, adjusting or tapering the drug (when medically possible) is the most direct solution. If Cushing’s syndrome is caused by a tumor, treating the tumor often resolves the fat redistribution over time.
For humps related to excess weight, regular exercise can make a meaningful difference. Research shows that consistent exercise programs reduce abdominal and central fat deposits significantly, sometimes independent of overall weight loss. Combined exercise programs (mixing aerobic activity with resistance training) have been shown to reduce waist circumference by nearly 4 centimeters on average compared to inactive controls. These programs are most effective when sustained for more than 12 weeks, reinforcing that long-term habit changes matter more than short bursts of activity.
In cases where the hump persists despite addressing the underlying cause, or where it causes physical discomfort, liposuction of the fat pad is an option. This is most commonly used for HIV-related lipodystrophy or persistent deposits after Cushing’s treatment. The fat can sometimes return if the underlying condition isn’t fully controlled.