Abstract:

Erythema nodosum (EN) is a common sign in department of dermatology and can be seen in systemic multiple system diseases. The purpose of this article is to explore the clinical features of erythema nodosum and to evaluate its diagnostic value for active tuberculosis (TB). Clinically, erythema nodosum presents with a sudden onset of red, painful, subcutaneous soft nodules and plaques, mainly localized to the extension of calf. EN may be associated with a variety of conditions such as infection, medications, sarcoidosis, pregnancy, inflammatory bowel disease, oral contraceptive, autoimmune disease, antibiotics, hormone response, lymphoma and other malignancy causes. The causes are unclear in around 50% of cases. It is well known that EN is a delayed hypersensitivity reaction induced by various stimulants. The clinical diagnosis for the atypical cases mainly depend on the biopsy or diagnostic treatment. Because of the complex etiology of EN, systemic diseases such as skin tuberculosis, leprosy, sarcoidosis and nodular arteritis need to be excluded. In the TB epidemic area, Mycobacterium tuberculosis infection (MTI) and active tuberculosis are closely related to EN. It is helpful to improve the EN symptoms, prevent EN relapse and control the active TB conditions through anti-tuberculous treatment in the patients who have active TB combined with EN and MTI with EN. EN can be associated with systemic multisystem diseases including tuberculosis, but further studies need to be done to reveal the underlying causes of EN. EN may be an early symptom of TB. It can be helpful for early diagnosis and treatment of the patients who have MTI with EN or TB with EN by the combination of tuberculin skin test (TST), acid-fast bacillus (AFB) detection and imaging techniques or diagnostic anti-tuberculosis treatment.

Key words: Erythema, nodosum, Tuberculosis, Disease attributes, Hypersensitivity, delayed, Causality, Literature review (subject)