Lipoatrophy, lipodystrophy, and panatrophy

The terms lipoatrophy and lipodystrophy usually infer loss of subcutaneous fat, and present as one or more depressions in the skin ranging from a few centimetres to greater than 20 cm in diameter. Localised panatrophy is a term reserved for partial or total loss of subcutaneous fat, atrophy of overlying skin, and sometimes atrophy or impaired growth of the underlying muscle or bone. 

This chapter is set out as follows: 

Acquired localised lipoatrophy and lipodystrophy, and localised panatrophy

These are the most common forms of lipoatrophy, there are several causes including:

Injections

• Steroid injections - a dent due to localised fat loss may appear at the site of a corticosteroid injection. This problem should be avoided by making sure that the injection goes in to the correct depth, and not in to the subcutaneous fat
• Insulin injections - diabetics may experience localised lipoatrophy at repeated injection sites
• Other injections - lipoatrophy has been reported to follow injections with penicillin, iron, growth hormone, vaccines, illicit drugs, and acupuncture 

Panniculitis

• Panniculitis is the term used for inflammation of subcutaneous fat. It is sometimes followed by permanent loss of fat
• For more information refer to the chapter Panicullitis 

Progressive hemifacial atrophy (Parry-Romberg syndrome)

• This is characterised by idiopathic thinning of skin, adipose tissue and underlying bone structures of one side of the face. One-half of the tongue is also usually affected
• Onset is usually during childhood

Localised panatrophy

This is rare. Two main types have been identified:

• Sclerotic panatrophy
  • ​Sclerotic change precedes the atrophy
  • Atrophy of the subcutis, and sometimes of underlying muscle and bone, may follow clinically and histologically typical morphoea, especially when the process begins in childhood and involves a limb
  • Sclerotic panatrophy may also occur in the absence of morphoea. The sclerosis involves subcutaneous tissue and muscle, and dense sclerotic scar‐like linear bands develop along a limb, or encircle the trunk or limb. Lesions tend to arise in childhood, enlarge, then cease progression after a few months of growth

• ​Panatrophy of Gower
  • ​No scleroderma, other sclerotic process, or inflammation is noted
  • Most cases occur in women, usually in the second to fourth decades
  • Most lesions arise on the back, buttocks, thighs or upper arms, but the forearms and lower legs can be affected
  • In each affected area, the subcutaneous tissue disappears and the overlying skin appears atrophic but is otherwise normal. There may be a single area of atrophy or two or more. In size they range from 2-20 cm across, and in shape they are very variable but are sometimes triangular or quadrangular
  • The atrophy reaches its maximum extent within a few months and then remains unchanged indefinitely

Acquired generalised lipodystrophy

Except for cases associated with HIV, these conditions are rare. There are several causes including:

Generalised lipodystrophy (Lawrence syndrome)

• Females are affected more than males
• In contrast to congenital lipodystrophy, patients with acquired generalised lipodystrophy (AGL) have normal fat density and distribution at birth. The onset of fat loss is typically insidious over months to years during childhood and adolescence, although rapid progression over weeks has been observed
• The extent and degree of fat loss is variable. Usual sites of involvement include the face, trunk, abdomen and extremities. Generally, marrow and retro‐orbital fat are preserved
• In addition to the loss of adipose tissue, patients often develop severe hepatic steatosis and fibrosis, severe insulin resistance, hypertriglyceridaemia and low serum HDL levels. Approximately 50% of the patients develop acanthosis nigricans

Partial lipodystrophy (Barraquer-Simons syndrome)

• This usually occurs before the age of 15 years
• Females are affected three times more than males
• Fat is lost symmetrically from the face and trunk, but the legs and hips are spared, indeed fat may accumulate in these sites in women 
• Approximately one‐third of patients develop mesangiocapillary glomerulonephritis (MCGN), usually more than 10 years after the onset of the lipodystrophy

HIV-associated lipodystrophy 

• Lipodystrophy in HIV infection is associated with highly active antiretroviral therapy (HAART) regimens containing protease inhibitor (PI) or nucleoside reverse transcriptase inhibitor (NRTI). It is now the most prevalent type of lipodystrophy, in which both lipodystrophy and lipohypertrophy may be observed
• Most patients present with a gradual loss of subcutaneous fat from the face, arms and legs. Facial involvement is present in 38–52% of HIV patients with lipodystrophy. Fat loss from the suprazygomatic and temporal regions of the face can be severe enough to impart a stigmatizing emaciated appearance
• Patients may also accumulate excess fat over the chin, breasts and waist, as well as over the upper back, producing a so‐called ‘buffalo hump’ 

Idiopathic lipodystrophy 

• In many cases of acquired lipodystrophy the cause is unknown

Congenital lipodystrophy

This can be generalised or partial. The established types include:

Generalised congenital lipodystrophy

• The congenital generalised lipodystrophies (CGLs; Berardinelli–Seip syndrome) are very rare autosomal recessive conditions
• The earliest sign in the neonate is a virtual absence of adipose tissue, followed by the development of a distinctive overall muscular appearance. The linear growth of an affected child is then usually significantly increased, associated with advanced bone age
• Systemic features include insulin resistance and hypertriglyceridaemia, which can be severe and cause acute pancreatitis. Acanthosis nigricans in the typical flexural sites develops next, together with fatty infiltration of the liver, which can lead to cirrhosis. A pseudoacromegalic appearance can appear, with minor enlargement of the mandible, hands and feet. With adolescence, girls can develop features similar to Polycystic Ovarian syndrome, together with clitoromegaly and subfertility

Familial partial lipodystrophy(FPLs)

• These are characterised by the development of an atypical distribution of subcutaneous adipose tissue, which begins in late childhood or early adult life
• In contrast to CGL, there is a normal distribution of body fat throughout infancy and early childhood
• There is a gradual loss of adipose tissue from both the upper and lower limbs, as well as from the buttocks and trunk
• In some people fat accumulates paradoxically on the face and neck
• Associated features develop in adulthood, including type-2 diabetes with acanthosis nigricans, which is usually minimal, and hypertriglyceridaemia. Hirsutism and menstrual abnormalities, which can mimic PCOS, may develop in about one‐quarter of affected women. Mild to moderate myopathy, cardiomyopathy and cardiac arrhythmias are sometimes associated with FPL

Treatment depends on the cause of the lipodystrophy, and may involve:

• Managing diabetes and elevated lipids 

• Altering HIV treatments 

• Cosmetic procedures such as fat transfer (moving fat from one part of the body to another), injectable filers and implants