Overlap syndrome: Juvenile dermatomyositis with systemic lupus erythematosus and lupus hepatitis in a child: An uncommon presentation

INTRODUCTION

Juvenile dermatomyositis (JDM) is a rare autoimmune disorder and a subtype of inflammatory myopathies.^[1] The incidence of JDM is 2–4/million.^[2] Childhood systemic lupus erythematosus (SLE) is a rare disease with a prevalence of 3.3−8.8/1,00,000 children.^[3] SLE-associated hepatitis, also known as lupus hepatitis, is characterized by subclinical and mild elevation of liver enzymes and affects 3–8% of SLE patients. Liver involvement occurs in 50–60% of SLE patients during their lifetime.^[4,5] Lupus hepatitis also indicates SLE activity in most cases.^[5] Overlap syndrome with JDM and SLE is rare and the occurrence of lupus hepatitis with overlap syndrome in a child is a unique entity. Herein, we describe a case of JDM with SLE who subsequently developed lupus hepatitis.

CASE REPORT

A 15-year-old boy was admitted to the dermatology inpatients in September 2020 with multiple painful joints of hands, knee, and elbow, diffuse asymptomatic erythema around the eye, chest, and neck, photosensitivity, weakness of proximal muscles of both arms and thighs and multiple painful ulcers on the back, buttocks, and elbow joint. Ulcers over the elbow joint were associated with chalky white discharge. There was no history of oral ulcers, Raynaud’s phenomenon, sclerodactyly, and dryness of mucosae. Family history was not significant.

On physical examination, we observed normal vital parameters, pallor, and myopathic gait. Mucocutaneous examination revealed heliotrope rash involving the periocular area and nasolabial fold [Figure 1a] and multiple erythematous grouped papules over bilateral interphalangeal and metacarpophalangeal joints [Figure 1b]. The patient had multiple ulcers over the trunk with irregular margins, sloping edges, and floor-slowing pale granulation tissue smeared with pus [Figure 1c]. Ulcer over the elbow joint showed chalky white discharge suggestive of calcinosis cutis. Scalp examination revealed diffuse non-cicatricial alopecia involving the occipital and bilateral temporoparietal area [Figure 1d]. Proximal muscles of bilateral upper and lower limbs showed reduced power with medical research counsel grade 3/5 except the hip abductor, which showed power of 2/5. The limb girth of the bilateral arm was reduced to 10 cm. The range of motion of bilateral knee and elbow joints was reduced. Nailfold capillaroscopy showed reduced capillary density and the presence of tortuous and dilated capillaries [Figure 2a]. The rest of the mucosae and systemic examination was within normal limits. Based on history and clinical examination, a provisional diagnosis of JDM was made.

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Figure 1:

(a) Diffuse violaceous facial erythema involving periocular area and nasolabial fold, (b) multiple violaceous papules were present over bilateral interphalangeal and metacarpophalangeal joints, (c) multiple ulcer over the trunk with irregular margin, sloping edges and floor slowing pale granulation tissue smeared with pus, and (d) diffuse non-cicatricial alopecia involving occipital and bilateral temporoparietal area.

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Figure 2:

(a) Nailfold capillaroscopy showing tortuous (black arrow) and dilated capillary (green arrow) and (b) hyperkeratotic mildly acanthotic epidermis with focal pigment incontinence in the upper dermis (Hematoxylin and eosin, magnification ×400).

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Laboratory investigations are shown in Table 1. Total and differential leucocyte counts and kidney function tests were within normal limits. Biopsy from the papule present over the interphalangeal joint showed hyperkeratotic, mildly acanthotic epidermis with focal pigment incontinence in the upper dermis [Figure 2b]. Myositis-specific antibody profile, electromyography, and direct immunofluorescence could not be done due to feasibility constraints.

DISCUSSION

Overlap syndrome is characterized by fulfillment of classification criteria for two or more autoimmune connective tissue diseases.^[6] Overlap myositis, defined as the presence of idiopathic inflammatory myositis (Polymyositis, dermatomyositis, etc.) with other connective tissue diseases, is a rare disease and its prevalence in patients with SLE is low (4–16%).^[7] Our patients also had positive U1-RNP antibodies but did not fulfill the criteria for mixed connective tissue disease. To the best of our knowledge, there has been only one case reported in the literature of JDM and SLE with hepatitis, though JDM with SLE has been reported.^[8,9] The previously reported cases of overlap syndrome are detailed in Table 2. Approximately 25–59% of the SLE patients develop transaminitis during their lifetime. The most commonly identified causes are drugs and viral hepatitis. However, in 28–42% of patients, in the absence of no obvious cause, it is attributed to SLE disease itself.^[4] Lupus hepatitis has a benign course, is associated with a good prognosis, and responds well to corticosteroid therapy with no long-term complications as compared to AIH which has a poor prognosis, and higher rates of progression to liver cirrhosis, hepatocellular carcinoma, and death.^[4,5]

CONCLUSION

With this case, we would like to draw attention toward the significance of regular and long-term follow-up in the early recognition of the complications and prompt initiation of treatment as it responds well to systemic immunosuppressants.