Erythema Induratum (Bazins Disease)

It is also known as Bazin's disease, nodular vasculitis and tuberculous erythema induratum.

The classical description of the disease is as a nodular eruption on the lower legs of young women 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.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.
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 but it may occur in other places too.
• About half of patients will give a past or present history of tuberculosis. This is most often pulmonary tuberculosis with cervical lymphadenopathy second.
• Tender erythematous nodules appear, usually on the lower leg. They run a chronic and recurrent course and may well heal with ulceration or depressed scars.
• The legs may be oedematous.
• There may be groups of small, tender, erythematous nodules.
• They are most often on the calves, with the shins involved less often. 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.
• They 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.

• 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. Erythema induratum rather than nodular vasculitis, 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. 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.

The treatment of tuberculosis is discussed in the article on that subject.
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.

If tuberculosis is the aetiology, 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.