Erythema Induratum (Bazins Disease)

Synonyms: Bazin's disease, nodular vasculitis, tuberculous erythema induratum, tuberculosum, tuberculosis cutis indurativa and nodose tuberculid.

Erythema induratum is a rare condition that classically produces painful, firm and sometimes ulcerated nodules on the lower legs (usually of young women) in association with tuberculosis.

In 1945, the term nodular vasculitis was coined to describe chronic inflammatory nodules of the legs that showed histopathological changes similar to those of erythema induratum but without an association with tuberculosis. The vasculitis is of the larger vessels with panniculitis (an inflammation involving subcutaneous fat and occasionally muscle with or without vasculitis).¹

Erythema induratum and nodular vasculitis had been seen as the same disease for many years but nodular vasculitis is now considered to be a multifactorial syndrome of lobular panniculitis in which tuberculosis may or may not be one of the various aetiologies. It is now classified as erythema induratum of Bazin type and nodular vasculitis or erythema induratum of Whitfield type. Bazin type is associated with tuberculosis. Whitfield type is not.

The disease or diseases represent an inflammatory reaction. One antigen is Mycobacterium tuberculosis. Patients with erythema induratum have a strongly positive tuberculin skin test and a marked increase in their peripheral T lymphocyte response to purified protein derivative (PPD) of tuberculin, which is a delayed (type IV) hypersensitivity reaction. In cases of erythema induratum with a negative tuberculin test the cause is unknown but the possibility of hepatitis C being implicated has been suggested.²

• The disease is still seen in countries where tuberculosis is rife but it is rarely seen in western societies, and when it is, the type is more often Whitfield than Bazin. Erythema induratum is still prevalent in India, Hong Kong, and South Africa.
• There is a marked female preponderance.
• The commonest presentation is in a young woman in her 20s but it may present at a later age.

• The usual site of the lesions is the lower legs (calves, with the shins involved less often) but it may occur in other places too.
  The trunk, buttocks, thighs, and arms can be involved but this is much rarer. The nodules are usually grouped on the lower third of the legs, especially around the ankles.
• The nodules are tender and erythematous.
• The nodules may ulcerate with bluish borders, and cold weather may be the precipitating factor. This produces irregular, shallow ulcers that may cause permanent scarring with hyperpigmentation of the lesions.They may run a chronic and recurrent course.
• The legs may be oedematous.
• About half of patients will give a past or present history of tuberculosis. This is most often pulmonary tuberculosis with cervical lymphadenopathy second.

• Cold Panniculitis
• Chilblain
• Lymphoma
• Erythema nodosum leprosum
• Dermatitis artefacta
• Alpha-1 antitrypsin deficiency panniculitis
• Lupus panniculitis

• FBC and ESR
• CXR
• If a Mantoux test is performed it should be at a 1:10,000 dilution as the response can be very marked. Unlike nodular vasculitis, erythema induratum is seen as a tuberculous disease and a strongly positive Mantoux response is regarded as an important diagnostic feature.
• A lesion may be biopsied and polymerase chain reaction provides rapid and sensitive detection of M. tuberculosis in a formalin-fixed, paraffin-embedded specimen. This can differentiate tuberculous disease from other aetiologies. A study from Spain used PCR amplification on skin biopsy specimens and found positive for M. tuberculosis in 77%. There was no correlation with clinical findings.³
• An excision biopsy is usually recommended, going down to an adequate level of subcutaneous fat. Stains for bacteria and fungi may be used and an attempt to culture the tubercle baccillus and other organisms. Histological features are characteristic.^4,5 Specimens for culture must be sent to the laboratory without delay and they must not be placed in formalin.

• By far the most important associated disease is tuberculosis, old or active. Erythema induratum of Bazin and renal tuberculosis can be associated.⁶
• A variation of erythema induratum (nodular tuberculid) with a granulomatous vasculitis occurring at the dermohypodermal junction has been reported in 5 patients with HIV disease.⁷
• Episcleritis in children has also been reported.⁸

• See article on Treatment of Tuberculosis.
• Potassium iodide may be used.
• Bed rest may be indicated and even steroids but they must be used with caution in old or active tuberculosis.

If not properly treated, the lesions can be persistent, ulcerated and cause scars.

When tuberculosis is the cause, then if it is correctly treated the lesions will disappear. In nodular vasculitis where there is no suggestion of tuberculosis being involved, there would presumably be no response to tuberculous chemotherapy.

Pierre-Antoine-Ernest Bazin was born in 1807 and died in 1878. He was the son and grandson of physicians. He studied in Paris. He took an interest in dermatology and that is where he made his name. Alibert-Bazin syndrome is the old name for mycosis fungoides. He established that the same fungi caused tinea capitis and affected the beard and body. He investigated scabies and acne and later devoted himself to parasitology. He described erythema induratum in 1861.