Localized lipodystrophy (ORPHA:79088)
A rare group of acquired lipodystrophies that are characterized by loss of subcutaneous tissue from generally small regions of the body, either single or multiple areas, and are not typically associated with metabolic complications. Some cases may involve lipohypertrophy (insulin). This group includes pressure-induced localized lipoatrophy, drug-induced localized lipodystrophy, panniculitis- induced localized lipodystrophy, centrifugal lipodystrophy, and idiopathic localized lipodystrophy.
Epidemiology
The term covers a heterogeneous group of conditions for which the prevalence varies according to the cause.
Clinical description
Localized lipohypertrophy involves small body areas, manifesting as either a soft bump or a depression in the soft tissue, and are not usually accompanied by a metabolic syndrome. They are most frequently observed in association with repeated mechanical microtraumatism (pressure induced localized lipoatrophy) such as drug injection, but may also be seen as the sequelae of an inflammation (panniculitis-induced localized lipodystrophy). Drug-induced localized lipodystrophy is often observed in diabetes associated with steroid or antiretroviral treatment leading to possible android obesity, and sometimes a lipoatrophy of Bichat balls under antiretroviral drugs. Centrifugal lipodystrophy is characterized by fat loss spread in a centrifugal pattern from abdomen and groin area and is associated with peripheral panniculitis. It begins in infancy, stops spreading between the ages of 3 and 8 and then in most cases, resolves by itself. Panniculitis-induced localized lipodystrophy is characterized by an initial development of panniculitis followed by localized fat loss when these lesions heal. The disease is associated with serum ANA and anti dsDNA antibodies, patients may also have concurrent autoimmune diseases. Localized lipoatrophy is not painful but can induce discomfort, especially when they are localized in a support zone such as the bottom, or dressing difficulties or aesthetic prejudice.
Etiology
Localized lipodystrophy is generally iatrogenic and secondary to medication injections (somatostatin analogs, pegvisomant, insulin), vaccines or repetitive pressure trauma. In addition certain medications can induce localized lipodystrophy such as steroids or antiretroviral treatment, or it can be triggered by panniculitis (such as nodular non-suppurative panniculitis, Weber-Christian syndrome). The etiology for idiopathic localized lipodystrophy and centrifugal localized lipodystrophy remains unknown.
Differential diagnosis
Differential diagnoses may include scleroderma, idiopathic dermal atrophy, idiopathic atrophoderma of Pasini and Pierini, and Gowers panatrophy.
Antenatal diagnosis
Not applicable.
Genetic counseling
Not applicable.
Management and treatment
Treatment should revolve around elimination of the cause whenever possible: modification of the injection technique or plastic surgery if necessary. Localized lipodystrophy associated with insulin therapy usually resolves in a few weeks after changing the site of injection and modification of the length of the needle.
Prognosis
The prognosis depends on the cause but is more severe in case of panniculitis.

                            Last update: 
                            September 2019


                            - Expert reviewer(s): 
                            Pr Marie-Christine VANTYGHEM