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- Dermatology
- Infectious diseases
- TB and other respiratory infections
- General practice / family medicine
- Drugs: infectious diseases
Description
An adolescent female presented with problems of low-grade fever with evening rise, night sweats and unintentional weight loss of 5 kg of 2 months duration. On examination, she had pallor and bilateral cervical lymphadenopathy. Cutaneous examination revealed multiple skin coloured to erythematous spiny, peri-follicular papules over the trunk, neck and upper and lower extremities suggestive of lichen scrofulosorum (LS) as shown in (figures 1 and 2). Her systemic examination revealed no abnormal findings. Based on her presentation, tubercular lymphadenitis was suspected. Investigations revealed haemoglobin of 8.5 g/dL with a normocytic normochromic picture. Her erythrocyte sedimentation rate (ESR) was raised (78 mm/hour), and the tuberculin test showed an induration of 22 mm. A lymph node biopsy from the right cervical lymph node revealed multiple caseating granulomas. Ziehl Neelson stain from the sample showed numerous acid-fast bacilli, and GeneXpert for Mycobacterium tuberculosis was positive. Concomitant biopsy taken from the skin lesion also showed caseating granuloma in the dermis surrounding the hair appendages as shown in (figures 3 and 4). However, the Ziehl Neelson stain from the sample was negative for acid-fast bacilli. Contrast-enhanced CT of the neck and chest showed necrotic cervical nodes at level IV/V on both sides and hilar lymph nodes. Based on clinical–radiological and microbiological evidence, we established the diagnosis of cervical lymph node tuberculosis. The patient was started on anti-tuberculosis treatment (ATT) with rifampicin, isoniazid, pyrazinamide and ethambutol. She showed significant improvement, as evidenced by the disappearance of skin lesions and weight gain.
Tuberculid refers to a hypersensitivity skin reaction resulting from the presence of tuberculosis antigen elsewhere in the body. LS is the most prevalent form of tuberculid, characterised by multiple, grouped, perifollicular lichenoid papules.1 Among patients diagnosed with cutaneous tuberculosis, LS cases account for 15.2%.1 2 The trunk is often the most affected area, and the condition typically occurs in children and young adults, especially those suffering from tuberculosis of the lymph nodes.3 4 On initiation of anti-tuberculosis therapy to manage the primary tuberculosis foci, LS typically resolves entirely within 2–3 months, as evidenced in figure 5.
Learning points
Morphological similarity of lichen scrofulosorum (LS) with various close resembling conditions, its waxing and waning course may lead to diagnostic difficulty, thereby necessitating a high index of suspicion and appropriate evaluation of the underlying tuberculosis (TB) focus.
LS histopathological examination reveals periappendageal caseating granulomas with no TB bacilli.
Management of primary TB focus leads to spontaneous resolution of the skin lesions.
Ethics statements
Patient consent for publication
Footnotes
Contributors The following authors were responsible for drafting of the text, sourcing and editing of clinical images, investigation results, drawing original diagrams and algorithms, and critical revision for important intellectual content: all authors. The following authors gave final approval of the manuscript: all authors.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.