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Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Panniculitis refers to a group of conditions that involve inflammation of the fat under the skin. Despite having very diverse causes, most forms of panniculitis have the same clinical appearance. The diagnosis is established by a skin biopsy as there are characteristic microscopic features depending on the cause.

The classification of panniculitis is complicated but, in general, different types can be divided into mostly septal or mostly lobular panniculitis depending on where the microscopic inflammation is most concentrated. In reality, most types of panniculitis have both lobular and septal inflammation. Further classification is based on whether or not there is inflammation involving the blood vessels of the fat, i.e. vasculitis.

Classification of panniculitis

Mostly septal panniculitis with vasculitis

Mostly septal panniculitis without vasculitis

Mostly lobular panniculitis with vasculitis

Mostly lobular panniculitis without vasculitis

Clinical features of panniculitis

An area of skin involved with panniculitis feels thickened and woody to touch. It may or may not demonstrate discolouration of the overlying skin, either reddening or darker, brownish pigmentation. The area is often tender. Most often, the affected areas appear as raised nodules or lumps under the skin, but may be a plaque or large flat area of thickened skin. When the inflammation has settled, a depression in the skin may be left behind temporarily or permanently (localised lipodystrophy)

Panniculitis Panniculitis Panniculitis

How is panniculitis diagnosed?

Panniculitis is diagnosed by a combination of clinical features, biopsy findings and microbiological culture. Sometimes other investigations are necessary.

Treatment of panniculitis

Treatment of panniculitis includes:

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Author: Dr Amy Stanway MBChB, Registrar, Department of Dermatology, Waikato Hospital, Hamilton, New Zealand.

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