Panniculitis

Synonyms

None.

Epidemiology

Rare depending on underlying cause.

Definition

A heterogeneous group of diseases showing inflammation of subcutaneous adipose tissue.

Aetiology & Pathogenesis

Various underlying causes of suppurative and non-suppurative panniculitis:

As part of morphea or scleroderma
Due to alpha₁-antitrypsin deficiency
Post trauma
Post infection
Subcutaneous panniculitis T-cell lymphoma
Lupus profundus

In association with:

Tuberculosis (erythema induratum)
Pancreatic disease
Perinatal asphyxia or hypothermia (sclerema neonatorum and subcutaneous fat necrosis of the newborn)
Post-steroid therapy
Autoimmune dermatoses (systemic lupus erythematosus; dermatomyositis)
Post trauma including surgery
Post infection
Chronic venous insufficiency (lipodermatosclerosis).

There may be overlapping causes of panniculitis (e.g. lupus erythematosus and trauma).

Signs & Symptoms

Can be asymptomatic or affected areas tender on pressure. Fever, joint pains, systemic upset and ulcers may be present. Signs on examination of other systems may be helpful to make a clinical diagnosis.

Localisation

Varies according to underlying cause. Lupus panniculitis: upper torso and hips. Alpha₁-antitrypsin deficiency-associated panniculitis: pelvic girdle. Erythema induratum and lipodermatosclerosis: lower legs.

Classification

Predominantly septal panniculitis:

As part of morphea or scleroderma
Due to alpha₁-antitrypsin deficiency
Erythema nodosum

Lobular and mixed septal/lobular panniculitis: all other types listed above.

Laboratory & other workups

Depending on the underlying diagnosis.

Dermatopathology

Usually not necessary. Isolated pure forms of panniculitis are rare, and clinical and other laboratory features should be considered.

Course

Depending on the underlying cause. Some forms will burn out leaving hard permanent scars. Longstanding and migrating subtypes exist.

Complications

Depending on the underlying cause.

Diagnosis

Clinical features. Occasionally biopsy may be required.

Differential diagnosis

Polyarteritis nodosa, nodular vasculitis and, cellulitis, cutaneous T-cell lymphoma.

Prevention & Therapy

Depending on aetiology.

Special