A “Buffalo Hump,” or dorsocervical fat pad, is a noticeable accumulation of fat tissue at the base of the neck and upper back. This physical change often serves as a visible sign of an underlying medical issue affecting the body’s metabolism and fat distribution. While sometimes related to simple weight gain, its development is frequently linked to hormonal imbalances, medication side effects, or metabolic disorders. Understanding the specific cause is necessary because treatment directly addresses the root problem.
Defining the Dorsocervical Fat Pad
The dorsocervical fat pad is a collection of adipose tissue located primarily in the posterior region of the neck, typically spanning from the third cervical vertebra down to the third thoracic vertebra. This accumulation is a type of localized lipohypertrophy, meaning an abnormal overgrowth of fat cells in a specific area. Studies suggest the severity of the dorsocervical hump has a low correlation with overall obesity, indicating a mechanism beyond simple weight gain is often involved.
It is important to distinguish this condition from a “Dowager’s Hump,” which is the colloquial term for kyphosis. Kyphosis is a structural change involving an excessive outward curvature of the upper spine, often caused by osteoporosis or poor posture. While poor posture can create the appearance of a hump, the true dorsocervical fat pad is composed solely of fat tissue, whereas kyphosis involves a change in the bone structure itself.
Endocrine and Hormonal Drivers
The most significant medical cause of a dorsocervical fat pad is Cushing’s syndrome, characterized by prolonged exposure to high levels of the hormone cortisol. Cortisol, produced by the adrenal glands, is a glucocorticoid hormone that plays a role in stress response and metabolism. Cushing’s syndrome causes a redistribution of fat throughout the body.
When cortisol levels are chronically elevated, the body shifts where it stores fat, leading to central obesity, a rounded “moon face,” and localized accumulation at the upper back. The excess cortisol can originate internally (endogenous Cushing’s syndrome), such as from a tumor on the pituitary or adrenal glands. This overproduction leads to fat accumulation that is often harder and denser than typical body fat, reflecting the hormonal disruption.
Medication Side Effects and Metabolic Factors
Corticosteroid Use
Beyond naturally occurring hormonal conditions, external sources of glucocorticoids are a common cause of this fat accumulation. Long-term use of high-dose corticosteroid medications, such as prednisone, hydrocortisone, or dexamethasone, can mimic the effects of Cushing’s syndrome. These medications are prescribed for a variety of inflammatory and autoimmune conditions, but their use can lead to the same fat redistribution pattern seen with naturally elevated cortisol.
HIV Therapies
Another iatrogenic cause is the lipodystrophy associated with certain antiretroviral therapies used to manage Human Immunodeficiency Virus (HIV). While newer HIV medications are less likely to cause this side effect, older protease inhibitors were known to cause an abnormal fat distribution. This involves fat loss in some areas, like the face and limbs, and fat accumulation in others, including the upper back and abdomen.
Metabolic Factors
Metabolic factors, even without a formal hormonal disorder, also contribute to the development of a dorsocervical fat pad. General obesity and metabolic syndrome, a cluster of conditions including high blood pressure and insulin resistance, can increase the risk of fat accumulation in this region. The overall excess of body fat can deposit in the dorsocervical area, though this is often accompanied by more generalized fat deposition compared to the specific patterns seen with Cushing’s syndrome.