Clinico‐epidemiological profile of lichen scrofulosorum: a 22‐year, single‐center, retrospective study

Abstract

Background Lichen scrofulosorum (LS) represents immunologic reaction to the Mycobacterium tuberculosis antigen and presents with subtle, asymptomatic, grouped follicular papules over the trunk and shows good therapeutic response to antitubercular drugs. Objective To study the clinical and epidemiological characteristics of patients diagnosed with LS. Materials and Methods A single‐center retrospective review of patients diagnosed with LS from 1997 to 2018 was conducted. The data pertained to clinico‐epidemiological profile, BCG vaccination, Mantoux positivity, laboratory investigations, coexistent focus of tuberculosis, and response to antitubercular treatment (ATT). Results LS cases constituted 15.2% (221/1458) of all the patients diagnosed with cutaneous tuberculosis (CTB). Of these, 156 (70.5%) were pediatric patients. All patients presented with multiple follicular and perifollicular grouped papules. The trunk was the most common site involved (98.6%), followed by lower limb (25.33%), upper limb (15.83%), face (5%), and external genitalia (3.6%). Evidence of BCG vaccination and Mantoux test positivity was observed in 52.03 and 83.2%, respectively. Coexistent TB focus was detected in 134 (60.6%) patients in lymph nodes, lungs, abdomen, and unusual sites such as intracranial, endometrium, and eye. Twenty‐eight patients (12.66%) had coexistent other clinical forms of CTB. Clinical diagnosis of LS was confirmed on histology that revealed chiefly periappendageal epithelioid cell granuloma. Response to ATT was good with complete resolution of lesion in 8–12 weeks. Conclusion LS appears to be an underdiagnosed entity. Subtle and asymptomatic lesions of LS are often missed, thereby necessitating a high index of suspicion and appropriate evaluation of the underlying TB focus.

Co‐existence of atypical tuberculid with lupus vulgaris

“…6 LS mimicking various dermatoses including psoriasiform, eczematous, and pustular lesions have been highlighted earlier. 9 There have been few other isolated reports of atypical presentations of tuberculids including verrucous tuberculid, phlebitic tuberculids, and molluscum-like papules in adult patients. [12][13][14][15] Whereas, lesions in our patient were progressive, scaly hypopigmented macules, and skin colored to hypopigmented scaly papules.…”

“…Presence of mycobacterial DNA has been described by polymerase chain reaction (PCR) techniques on the skin biopsy samples of papulonecrotic tuberculids 7,8 . All types of tuberculids are reported in children, with lichen scrofulosorum (LS) being the most common 4–6,9 . Tuberculids, commonly described in association with tuberculosis of lymph nodes, lungs, and other organ systems, are rarely reported with CTB 1,9,10 .…”

“…7,8 All types of tuberculids are reported in children, with lichen scrofulosorum (LS) being the most common. [4][5][6]9 Tuberculids, commonly described in association with tuberculosis of lymph nodes, lungs, and other organ systems, are rarely reported with CTB. 1,9,10 We report a rare case with an atypical presentation of tuberculid with hypopigmented, scaly maculopapular lesions in association with lupus vulgaris.…”

Mycobacterial skin infection

“…Tuberculids are a form of hypersensitivity reaction to mycobacterial antigens in cutaneous blood vessels in patients with high immunity to M. tuberculosis . Their clinical appearance is heterogeneous: papulonecrotic lesions, lichen scrofulosorum , reported as the most common tuberculid lesion in children [ 19 ▪ ], and erythema induratum of Bazin (EIB), the latter is the most frequent form of tuberculid, commonly seen on the posterior part of the legs [ 20 ▪ ].…”

“…Thus, culture and amplification of M. tuberculosis DNA by PCR in skin biopsies are the gold standard for diagnosis [ 11 ]. M. tuberculosis cannot be found in smear nor cultured from tuberculids lesions, although mycobacterial DNA may occasionally be detected by PCR [ 2 , 19 ▪ ].…”