Lupus vulgaris of forearm
M Gupta, S Lehl
Citation
M Gupta, S Lehl. Lupus vulgaris of forearm. The Internet Journal of Dermatology. 2009 Volume 8 Number 1.
Abstract
A 58 year old diabetic hypertensive woman presented to medical outpatient clinic with history of painful reddish nodules on the right forearm of three months duration. She also had low grade fever and significant weight loss. The nodules appeared on the forearm three months back and progressively spread towards the hand. On examination gelatinous reddish-blue nodules some coalescing into indurated plaques were seen on the dorsum of hand and forearm.
Case report
A 58 year old diabetic hypertensive woman presented to medical outpatient clinic with history of painful reddish nodules on the right forearm of three months duration. She also had low grade fever and significant weight loss. The nodules appeared on the forearm three months back and progressively spread towards the hand. On examination gelatinous reddish-blue nodules some coalescing into indurated plaques were seen on the dorsum of hand and forearm.
Figure 1
There was no ulceration, crusting, scarring or sinus. There was no evidence of underlying osteomyelits or synovitis of wrist. There was no lymphadenopathy, hepatosplenomegaly or spinal tenderness. Her diabetic control was adequate. The tuberculin test was positive. The chest radiograph was within normal limits. ESR was 60 mm in first hour. A deep skin biopsy was performed. The histopathology showed caseating granulomas with epithelioid cells, giant cells, and lympho-mononuclear infiltrate consistent with lupus vulgaris, although no acid-fast bacilli were seen. With a presumptive diagnosis of cutaneous tuberculosis (lupus vulgaris), patient was started on short course antitubercular chemotherapy (2 months of HRZE followed by 4 months of HR). Patient showed clinical response (regression of lesions, weight gain and disappearance of fever) in the next 3 weeks and the diagnosis of lupus vulgaris was confirmed on the basis of response to treatment.
Discussion
Cutaneous tuberculosis is uncommon disease. It is a rare manifestation of extra-pulmonary tuberculosis with incidence of <1% in individuals attending dermatology clinics of countries with high prevalence of tuberculosis. It is much rarely seen in the developed countries. It preferentially affects women, and most frequently located on the neck, face and trunk. Lupus vulgaris is a variant of cutaneous tuberculosis. Other variants include scrofuloderm, tuberculous gumma, tuberculosis verrucosa cutis, tuberculids, and tuberculous chancre.
Lupus vulgaris is a chronic and progressive form of cutaneous tuberculosis. It may manifest clinically as plaque form, ulcerating form, vegetative form or nodular form. Histology shows typical granulomatous tubercle with epithelioid cells, Langhans giant cells, and a mononuclear infiltrate. Acid fast bacilli are rarely seen in the lesions. Mycobacterium tuberculosis is the most common isolate from the histopathological specimens of cutaneous tuberculosis, although Mycobacterium scrofulaceum and Mycobacterium avium complex may also be isolated in few cases1. Secondary changes like ulceration and scarring is common in lupus vulgaris leading to disfigurement. Long-standing lupus vulgaris may predispose to squamous cell carcinoma. Standard treatment protocols as for pulmonary tuberculosis are used to treat this condition.