Summary about Disease
Erythema induratum of Bazin (EIB), also known as nodular vasculitis, is a rare inflammatory skin condition characterized by painful, tender nodules and plaques, typically on the calves and lower legs. It's often associated with underlying tuberculosis (TB) infection, although not always. In some cases, it may be idiopathic (cause unknown) or associated with other systemic diseases.
Symptoms
Painful, red or purplish nodules and plaques, primarily on the calves and shins.
Lesions may ulcerate or leave scars.
Lesions are usually symmetrical (appear on both legs).
May be associated with fatigue, fever, or weight loss (especially if TB-related).
Causes
Tuberculosis (TB): The most common association. The skin lesions are thought to be a hypersensitivity reaction to Mycobacterium tuberculosis* antigens.
Idiopathic: In some cases, no underlying cause can be identified.
Other infections: Rarely, other infections (e.g., hepatitis B or C, streptococcal infections) may be implicated.
Autoimmune diseases: Some cases are associated with autoimmune conditions such as lupus erythematosus.
Medicine Used
Anti-tuberculosis therapy (ATT): If TB is confirmed or strongly suspected, a full course of ATT is essential.
Nonsteroidal anti-inflammatory drugs (NSAIDs): To manage pain and inflammation.
Corticosteroids (topical or oral): To reduce inflammation, but long-term use has potential side effects.
Potassium Iodide: Sometimes used to reduce inflammation.
Immunosuppressants: In severe or refractory cases, medications like dapsone, hydroxychloroquine, colchicine, or methotrexate may be considered.
Pentoxifylline: To improve blood flow and reduce inflammation.
Is Communicable
Erythema induratum of Bazin (EIB) itself is not communicable. However, if EIB is caused by an underlying active tuberculosis (TB) infection, *TB itself is communicable*. Transmission occurs through airborne droplets when a person with active TB coughs, sneezes, speaks, or sings.
Precautions
If TB is suspected/confirmed: Standard TB infection control measures are crucial to prevent spread (respiratory isolation, mask use, etc.).
General wound care: Keep lesions clean and covered to prevent secondary infection.
Avoid prolonged standing or sitting: Elevate legs to improve circulation and reduce swelling.
Compression stockings: Can help with circulation and reduce leg swelling.
Protect skin from trauma: Avoid tight clothing or footwear that may irritate lesions.
How long does an outbreak last?
The duration of an outbreak varies depending on the underlying cause and treatment. Without treatment, lesions can persist for months to years. With appropriate treatment, especially if TB-related, lesions may start to improve within weeks, but complete resolution can take several months. Recurrences are possible.
How is it diagnosed?
Clinical examination: Based on the characteristic appearance and location of the lesions.
Skin biopsy: Essential to confirm the diagnosis and rule out other conditions. Histopathology typically shows lobular panniculitis (inflammation of subcutaneous fat) with vasculitis (inflammation of blood vessels).
Tuberculosis testing: Mantoux test (TST), interferon-gamma release assay (IGRA), chest X-ray, and sputum cultures to detect TB infection.
Blood tests: To rule out other underlying conditions (e.g., autoimmune diseases).
Timeline of Symptoms
Initial Stage: Typically starts with the gradual development of small, deep-seated, tender nodules under the skin, usually on the calves.
Progression: Over weeks to months, these nodules enlarge and become red or purplish. They may coalesce to form larger plaques.
Ulceration: Some nodules may break down and ulcerate, leading to open sores.
Resolution: With treatment (or spontaneously in some cases), the inflammation gradually subsides, and the lesions heal. Scarring is common.
Recurrence: Relapses can occur, particularly if the underlying cause (e.g., TB) is not adequately treated.
Important Considerations
Ruling out TB is crucial: Even if the initial TB tests are negative, repeat testing may be necessary if clinical suspicion remains high.
Differential diagnosis: Other conditions that can mimic EIB include erythema nodosum, vasculitis from other causes, panniculitis, and deep fungal infections.
Long-term follow-up: Monitoring for recurrence and complications is important.
Consider underlying medical conditions: Evaluate for associated systemic diseases or risk factors.
Patient education: Counsel patients on the importance of adherence to treatment and lifestyle modifications.