Miliary gout: A rare case report from North India

Dear Sir,

The atypical presentations of gout include miliary, bullous, papular, ulcerative, and verrucous.^[1,2] Miliary gout presents as “milia-like” papules over the body. Herewith, we report a rare case of miliary gout to bring this to the notice of dermatologists and physicians for the early diagnosis and treatment of gout.

A 54-year-old man presented to the Department of Medicine with cardiogenic shock. He was a known case of rheumatic heart disease. A dermatology opinion was taken for cutaneous lesions.

There was a history suggestive of psoriasis for the past 7–10 years for which he used to apply topical steroid on and off. He had a history of intermittent pain over multiple joints including joints of the hands, wrists, elbows, knees, and ankle joints for the past two years. The pain was asymmetrical and was not associated with morning stiffness or history suggestive of enthesitis. Some of the affected joints showed erythematous swelling with mild or no associated pain. The patient did not get evaluated for the same and took over-the-counter analgesics with temporary relief. He complained of asymptomatic raised hard skin lesions over the body for the past one year. He was an occasional alcohol user. The patient had a body mass index of 24.9 kg/m², and on mucocutaneous examination, there were multiple hard, yellowish-white discrete, non-tender, papules over normal to erythematous appearing skin over bilateral shins [Figure 1], forearms, palms, and trunk. There was erythematous swelling over the second right metacarpophalangeal joint with evidence of yellowish-white nodules inside it [Figure 2]. Based on history and examination, differentials of miliary calcinosis cutis and miliary gout were kept. Punch biopsy from shin papule showed multiple nodular deposits of eosinophilic fibrillar to homogenous amorphous gouty deposits in the dermis surrounded by a palisade of histiocytes and histiocytic giant cells, characteristic of gouty deposits [Figures 3 and 4]. The biochemical analysis revealed a high serum uric acid level of 12.9 mg/dL, anemia of chronic disease, deranged kidney function test (urea 82 mg%, creatinine 2.1 mg%), high C-reactive protein (21.7 mg/dL), raised rheumatoid factor (64 IU/mL), and negative anti-cyclic citrullinated peptide (anti-CCP) antibody. Serum calcium, phosphate, and parathyroid hormone were normal. X-ray of the joints revealed juxtaarticular osteopenia. Based on the morphology of the cutaneous lesions, high serum uric acid level, and histopathology, a final diagnosis of miliary gout was made and the patient was advised to avoid alcohol, a diet low in meat, and start febuxostat 40 mg once daily. However, within a few days, the patient died due to cardiac failure.

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Figure 1:

Multiple hard, yellowish-white discrete, non-tender, and papules over normal to erythematous appearing skin over shin.

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Figure 2:

Erythematous swelling over second right MCP joint with yellowish-white nodules inside it (nodules are not clear in picture).

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Figure 3:

Eosinophilic amorphous gouty deposits with surrounding giant cells and lymphoid proliferation in the dermis (× 10, H and E Stain).

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Figure 4:

Eosinophilic amorphous gouty deposits with surrounding giant cells and lymphoid proliferation in the dermis (× 20, H and E Stain).

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Gout is a common systemic metabolic disorder caused by abnormal uric acid metabolism. Untreated gouty arthritis can result in intra-dermal and deeper deposition of monosodium urate (MSU) crystals in the fat usually over the peri-articular area, cartilage or over normal skin resulting in chronic cutaneous tophaceous gout.^[2] Individuals with long-duration gouty arthritis, psoriasis, renal insufficiency, and lack of consistent use of urate-lowering therapy (as in our case) are at high risk of intradermal tophi formation. Psoriasis predisposes to hyperuricemia by activating Th1 and Th17 pathways which play a role in the pathogenesis of gout. This common cytokine pathway might point toward the association between gout and psoriasis. In addition, an increased keratinocyte turnover rate leads to increased purine metabolites causing increased serum uric acid levels. Genetic factors and metabolic syndrome also link psoriasis with gout.^[3,4]

A miliarial gout is a rare form of chronic tophaceous gout, which presents as “milia-like” papules containing white, cream, or yellow-colored material on an erythematous base on the skin over various body parts.^[1] The pathogenesis of intra-dermal tophaceous gout is yet to be elucidated, but it has been hypothesized that the rate of formation of urate crystals exceeds the handling capability of macrophages or probably the failure of tissue macrophages to differentiate to an endpoint, which does not produce a proinflammatory response to MSU crystal uptake.

There are few reports of miliary gout worldwide [Table 1]. Diagnosis of cutaneous tophaceous gout can be made by seeing amorphous crystalline material with surrounding granulomatous inflammation in histopathology and negatively birefringent needle-like crystals on polarized microscopy. X-ray of joints in gouty arthritis shows juxtaarticular erosions with sclerotic margins and overhanging edges with normal periarticular bone density and preserved joint space until the disease has reached late stage but it can be normal (as seen in our patient) as mentioned in report by Aguayo et al.^[2] The main differential is rheumatoid arthritis with calcinosis cutis. Both can be differentiated by serological and biochemical investigations. In our patient, rheumatoid arthritis with calcinosis cutis was ruled out by normal biochemical profile, along with negative anti-CCP level and skin histopathology findings. Others include pseudogout, oxalosis, and rheumatoid nodules. They are tabulated in Table 2. The treatment of chronic gout aims to prevent gout progression and flares, eliminate any MSU deposits, and prevent further tophus formation. Xanthine oxidase inhibitors (febuxostat and allopurinol) are the first-line treatment options followed by uricosuric agents (probenecid). This case is interesting given a rare cutaneous manifestation of chronic gout, that is, miliary gout. This also intends to sensitize physicians and dermatologists about this rare entity for its early diagnosis and management to prevent catastrophic outcomes such as renal failure, cardiac failure, and death.