Acquired partial lipodystrophy (APL) is a rare condition characterized by the selective loss of fat tissue in specific body areas. Unlike general weight loss, APL involves an abnormal distribution of fat. As an “acquired” disorder, it develops after birth rather than being inherited. APL is one of several types of lipodystrophy.
Understanding How It Appears
APL typically manifests as a gradual reduction of subcutaneous fat from certain body regions. This fat loss most commonly affects the face, neck, arms, and chest, often appearing symmetrical. Also known as Barraquer-Simons syndrome, fat loss usually begins in the face and then extends downwards to the shoulders, upper limbs, and thorax.
Individuals with APL may exhibit a noticeable decrease in facial fat, leading to a gaunt or older appearance. The reduction in fat tissue can make underlying muscles and blood vessels more prominent. While the upper body experiences fat loss, the lower extremities, such as the hips, thighs, and gluteal regions, are generally spared. In some instances, particularly in females after puberty, excess fat may accumulate in these lower body areas, creating a contrasting appearance.
Exploring the Causes
The precise cause of APL is often not fully understood, and in many cases, it is considered idiopathic. However, leading theories point to immune system involvement. APL is frequently associated with autoimmune conditions, where the body’s immune system mistakenly attacks and destroys its own fat cells. Autoimmune diseases like systemic lupus erythematosus and dermatomyositis have been linked to APL.
Infections, particularly viral infections, are also suspected as potential triggers for APL. Measles, mumps, rubella, and HIV have been associated with its development. The onset of APL often occurs during childhood or adolescence, sometimes following an acute febrile illness.
A notable mechanism involves dysregulation of the complement system, a part of the immune system. Over 80% of individuals with APL have low levels of complement 3 (C3), a protein that plays a role in immune response. They also frequently have an autoantibody called C3 nephritic factor (C3NeF), which causes sustained activation and consumption of C3. While the exact way this dysregulation impacts fat tissue is still being researched, the connection is evident.
Identifying and Managing the Condition
Diagnosing APL primarily relies on a clinical examination identifying characteristic fat loss patterns. A thorough medical history is also important to understand the condition’s onset and progression. To support the diagnosis, blood tests check for complement system abnormalities, such as low C3 levels and C3 nephritic factor, common in APL. Testing for autoimmune markers may also be part of the diagnostic process.
Imaging studies, such as Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) scans, can confirm the extent and distribution of fat loss and help differentiate APL from other conditions. These scans provide detailed images of the body’s fat composition. A renal biopsy might be considered if there is suspicion of kidney involvement, as glomerulonephritis is reported in some patients with APL.
Managing APL often focuses on addressing visible changes and any associated health complications, rather than reversing the fat loss itself. For cosmetic concerns, options to restore lost volume include fat grafting, where fat is transferred from another body area, and dermal fillers, particularly for facial hollowing. Reconstructive surgery is another approach for significant volume restoration.
Medical management targets underlying immune system issues or metabolic complications. If an autoimmune component is present, medications like corticosteroids or immunosuppressants might be used. APL can sometimes be associated with metabolic changes such as insulin resistance, high triglycerides, or fatty liver disease. Management of these metabolic issues can involve dietary adjustments, exercise, and specific medications like metformin or fibrates. Regular medical follow-ups are important to monitor the condition’s progression, assess for any new complications, and adjust management strategies as needed.