Cutaneous tuberculosis (TB) is caused by Mycobacterium tuberculosis (M. tuberculosis) in a majority of cases and rarely by Mycobacterium bovis. It accounts for 0.1%–0.9% of the skin conditions among all dermatology outpatients in India. Cutaneous TB is a significant medical problem despite the availability of highly effective chemotherapy. It accounts for approximately 1.5% of all tuberculous manifestations.1
Scrofuloderma, also known as tuberculosis colliquativa cutis, is the most common form of cutaneous TB. It arises by direct extension of acid fast bacilli from an underlying tuberculous focus into the skin. Cervical lymph nodes are the most common foci; however, inguinal, axillary, submandibular, supraclavicular, and epitrochlear lymph nodes may also be involved.2-3 Primary infection of the bone, intestinal Koch, and hepatic TB are sources of scrofuloderma in children.
A 28 years old man presented with a 5-month history of multiple non-healing and painless ulcerative lesions with purulent discharge on the left side of his abdomen. He had a low-grade fever and decreased appetite, and he had lost a significant amount of weight during the past year. He had been diagnosed with intestinal TB 9 months previously by fine-needle aspiration biopsy, which revealed multiple coalescent granulomas in the mucosa and submucosa. The patient was started on anti-tubercular drugs, but he discontinued treatment. He had no family history of TB.
Physical examination revealed four ulcers of varying sizes on the left side of the abdomen, the largest measuring 3 cm × 5 cm (Fig. 1). The ulcers were suppurative and well-demarcated, and they had elevated borders with undermined non-tender edges. The surrounding skin was edematous and pigmented. There was no evidence of lymph node involvement. The patient had no history of trauma. His vitals were as follows: pulse rate of 74 beats/minutes, respiratory rate of 22 breaths/minutes, and blood pressure of 130/80 mm Hg. Systemic examination revealed no abnormalities. The results of a complete blood count, urinalysis, and biochemical analysis were normal. The patient's erythrocyte sedimentation rate was 40 mm/h in the first hour. The result of an antibody test for human immunodeficiency virus was negative. The Mantoux test was positive (20 mm/72 h). Ziehl–Neelsen (ZN) staining of impression smears from the ulcerative lesions showed the presence of acid-fast bacilli (Fig. 1). Chest X-ray examination revealed no abnormalities. Fungal and aerobic bacterial cultures were negative. Histological examination showed mature squamous cells forming epithelioid granulomas with multinucleated giant cells, caseous necrosis, and mixed inflammatory cells in the dermis. Cultures of the skin biopsy on Lowenstein–Jensen media showed growth of M. tuberculosis after 8 weeks. PCR for the detection of M. tuberculosis was conducted on a biopsy specimen, and the result was positive.
The patient was diagnosed with scrofuloderma based on his clinical examination findings, the presence of acid-fast bacilli on ZN staining, positive culture, and positive PCR. He began treatment with an anti-tubercular regimen that included isoniazid, rifampicin, ethambutol, and pyrazinamide. The follow-up showed that the cutaneous lesions regressed and the ulcer healed after 18 months. The authors confirmed that the patient agrees to publish the case.
Globally, an estimated 10 million people fell ill with TB in 2019.4 Cutaneous TB remains a rare infection, with an incidence of 3.5% reported among patients with organ TB. Scrofuloderma is the commonest form of cutaneous TB,5 and starts as a painless subcutaneous nodule that ruptures, giving rise to shallow ulcers with undermined edges and granulation tissue at the base. The disease has a chronic, insidious course, leading to formation of intermittently discharging sinus tracts that heal with characteristic puckered scarring and producing irregular adherent masses that are densely fibrous in places.6
Diagnosis of scrofuloderma is always challenging because the clinical appearance of the lesions is not always characteristic and a positive culture is not always obtained. Biopsy from the periphery of the lesion may show granulomas with caseous necrosis, the center of which is dominated by necrotic and abscess material with inflammatory infiltrates. In the epidermis, scarring and atrophic changes often predominate. M. tuberculosis bacilli are easy to identify in the purulent discharge or biopsy tissue. The tuberculin test is usually positive.7
Scrofuloderma may be a manifestation of systemic TB or result from direct extension or hematogeneous spread of the infection. The incidence of systemic involvement is reportedly 35% in adults with scrofuloderma. PCR has increased the sensitivity of the overall detection of cutaneous TB with the possibility of earlier initiation of treatment.8
There are several other differential diagnoses for discharging sinuses, such as atypical mycobacterial infection, sporotrichosis, botryomycosis, actinomycosis, and nocardiosis.2 PCR and histopathology can easily distinguish between atypical mycobacterial infection from M. tuberculosis. Actinomycosis presents with multiple discharging sinuses with typical sulfur granules. Nocardia spp. appear as branching filamentous bacilli at right angles. The absence of fungal hyphae on histopathology leads to exclusion of sporotrichosis. Botryomycosis is diagnosed by the presence of bacteria in pus; it is mainly found in immunocompromised patients, and the lesions usually appear on the extremities.
Cutaneous TB is treated according to the recommendations for extrapulmonary TB. Recommended treatment includes a 2-month four-drug regimen (isoniazid, rifampicin, pyrazinamide, and ethambutol) followed by a 4-month two-drug regimen (isoniazid and rifampicin). Fixed-dose combinations should preferably be used. The World Health Organization recommends that daily dosing throughout the duration of the above-mentioned therapy is optimal for all patients who have been newly diagnosed with TB.9
The response to anti-tubercular treatment alone as a primary therapy is usually good. However, surgery, such as electrosurgery, cryosurgery, and curettage with electrodessication of affected nodes, can also be considered as an adjunctive measure.
We have herein presented a case involving a patient with a chronic, non-healing ulcers, which is a common presentation of scrofuloderma. Diagnosis of scrofuloderma may pose a challenge. However, a proper history and thorough examination with relevant investigations, such as ZN stain of the tissue sample and PCR, can facilitate rapid diagnosis of the infection and early initiation of treatment.
. Kumar B, Muralidhar S. Cutaneous tuberculosis: a twenty year prospective study. Int J Tuberc Lung Dis 1999;3(6):494–500.
. Tappeiner G. Wolff K, Goldsmith LA, Katz SI, et al. Tuberculosis and infections with atypical mycobacteria. Fitz Patrick's Dermatology in General Medicine 7th ed.NewYork: McGraw-Hill; 2008;1768–1778.
. Kumar B, Rai R, Kaur I, et al. Childhood cutaneous tuberculosis: a study over 25 years from northern India. Int J Dermatol 2001;40:26–32. doi:10.1046/j.1365-4362.2001.01165.x.
. Global Tuberculosis Report 2020, World Health Organization Executive Summary: 3.
. Terranova M, Padovese V, Fornari U, et al. Clinical and epidemiological study of cutaneous tuberculosis in Northern Ethiopia. Dermatology 2008;217(1):89–93. doi:10.1159/000128284.
. Sehgal VN, Wagh SA. Cutaneous tuberculosis. Current concepts. Int J Dermatol 1990;29:237–252. doi:10.1111/j.1365-4362.1990.tb02554.x.
. Barbagallo J, Tager P, Ingleton R, et al. Cutaneous tuberculosis: diagnosis and treatment. Am J Clin Dermatol 2002;3:319–328. doi:10.2165/00128071-200203050-00004.
. Hsiao PF, Tzen CY, Chen HC, et al. Polymerase chain reaction based detection of Mycobacterium tuberculosis in tissues showing granulomatous inflammation without demonstrable acid-fast bacilli. Int J Dermatol 2003;42:281–286. doi:10.1046/j.1365-4362.2003.01461.x.
. Treatment of Tuberculosis: Guidelines. 4th ed.Geneva: World Health Organization; 2009. (WHO/HTM/TB/2009.420).