Case Reports

Erythema Induratum of Bazin Presenting as Peripheral Neuropathy

Author and Disclosure Information

Erythema induratum of Bazin (EIB) is a rare tuberculid that typically affects middle-aged women. We report a unique case of EIB in a 57-year-old 
Hispanic woman who presented with recurrent painful plaques and nodules on the lower extremities, specifically on the pretibial area of the legs and dorsal aspect of the feet, with a severe burning sensation on the feet that resolved after antituberculosis therapy. We review the characteristics of EIB and examine how the unique presentation of peripheral neuropathy may relate to the pathophysiology of this disease.

Practice Points

  • Erythema induratum of Bazin (EIB) is a type of nodular vasculitis related to tuberculosis and 
commonly presents with plaques and nodules on the lower extremities.
  • Peripheral neuropathy may manifest as a result of a hypersensitivity reaction to tuberculosis antigens 
causing tissue and nerve damage.
  • Treatment of EIB and other cases of nodular vasculitis should be directed at the underlying cause of 
the immune response.


 

References

Case Report

A 54-year-old Hispanic woman with a history of type 2 diabetes mellitus and hyperlipidemia presented with recurrent painful plaques and nodules on the bilateral lower extremities and a severe burning sensation on the feet of 3 years’ duration. The patient denied experiencing any associated fevers, chills, night sweats, weight loss, joint aches, cough, or shortness of breath. She had a history of pustular psoriasis and reported a positive purified protein derivative (PPD)(tuberculin) skin test approximately 40 years prior.

She presented with a 4×4-cm, poorly defined, tender, indurated plaque on the middle of the left shin and a 2×3-cm, red-brown plaque on the dorsal aspect of the left foot (Figure 1). No lymphadenopathy or any other abnormalities were noted. The clinical differential diagnosis included various panniculitides, such as erythema nodosum, erythema induratum of Bazin (EIB), and lupus panniculitis, as well as other conditions, including polyarteritis nodosa, sarcoidosis, Sweet disease, deep fungal and mycobacterial infections, and cutaneous lymphoma.

Figure 1. Erythematous indurated plaques on the middle of the left shin (A) and on the dorsal aspect of the left foot (B).

Two skin biopsies taken for histopathologic evaluation revealed primarily granulomatous lobular panniculitis with foci of microthrombi and vasculitis (Figure 2). These findings were consistent with nodular vasculitis. Acid-fast bacillus and Gomori methenamine-silver stains were negative for mycobacterial or fungal organisms. Tissue cultures also were negative. Results from a complete blood cell count, chemistry panel, thyroid and liver function tests, hepatitis panel, and rapid plasma reagin test were unremarkable. Immunologic markers, including antinuclear antibody, antineutrophil cytoplasmic antibody, rheumatoid factor, and cryoglobulins, also revealed no abnormalities. A chest radiograph showed scarring in the suprahilar region of the upper lobe of the left lung consistent with a prior case of pulmonary tuberculosis, and exposure to Mycobacterium tuberculosis was confirmed with an IFN-γ release assay (IGRA) result of 1.49 IU/mL (>0.34 IU/mL indicates positive test). These findings from clinical and histopathologic examination as well as laboratory tests were consistent with a diagnosis of EIB.

Figure 2. Granulomatous lobular panniculitis (A)(H&E, original magnification ×40) with foci of microthrombi and vasculitis (B and C)(both H&E, original magnifications ×200).

Standard antituberculosis therapy with rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) was simplified to rifampin and isoniazid due to her inability to tolerate the full regimen because of gastrointestinal tract upset and diarrhea. After 6 months of therapy, a repeat IGRA decreased to 0.43 IU/mL, and the painful plaques and nodules on the lower extremities and burning sensation in the feet completely resolved.

Comment

Our case of EIB associated with peripheral neuropathy is a unique presentation of lesions on the pretibial area of the bilateral legs and dorsal aspect of the feet. We confirmed the presence of latent tuberculosis infection with a chest radiograph and an IGRA. Symptoms of peripheral neuropathy resolved after antituberculosis treatment, which suggests an immune-mediated mechanism of neuronal damage from circulating tuberculosis antigens.

Pathogenesis

Although erythema induratum was first described by Ernest Bazin in 1861, it was not until the early 1900s that the link between tuberculosis and erythema induratum was made by French dermatologists.1,2 Around the same time, similar cases of erythema induratum were discovered in England with no evidence of tuberculosis, which led to the distinct classification of erythema induratum of Whitfield (EIW). This classification described these nontuberculoid cases.1,2 In 1945, Montgomery et al3 in the United States coined the term nodular vasculitis for EIW and categorized its clinical features and histopathology as separate from EIB.3 Today, some authors use EIB, EIW, and nodular vasculitis interchangeably and believe they all are the same entity.2 We use EIB for all cases related to tuberculosis and nodular vasulitis when referring to all other etiologies, including nontuberculoid bacterial infections, chronic hepatitis B and C virus, thrombophlebitis, hypothyroidism, and rheumatoid arthritis.4,5

Erythema induratum of Bazin, lichen scrofulosorum, and papulonecrotic tuberculids are considered tuberculid diseases and are thought to be caused by hypersensitivity reactions to mycobacterial antigens rather than local mycobacterial infections. Tuberculids are believed to be a reaction to an id reaction of circulating mycobacterial antigens in the setting of latent or active tuberculosis infection. The basis for this view is that mycobacteria cannot be cultured or visualized from lesions in tuberculid diseases.6 Cutaneous tuberculosis, such as scrofuloderma, miliary tuberculosis, tuberculosis chancre, lupus vulgaris, and gummatous tuberculosis, differ from EIB and other tuberculid diseases in that mycobacteria can be cultured and visualized on histologic examination with Ziehl-Neelsen staining.6 The pathology of cutaneous tuberculosis results from a mycobacterial infection of the skin, and cutaneous tuberculosis diseases are categorized as multibacillary or paucibacillary based on the number of organisms visualized in biopsies.

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