Painful Yellow-White Nodules Over Feet in an Alcoholic Male

Dear Editor, Gout is a disorder of uric acid metabolism which usually presents with painful mono-arthritis to a physician. However, in the absence of joint symptoms, it can present to a dermatologist with painful nodules over the skin. In such cases, clinical and dermoscopic evaluation can aid in early diagnosis and referral to the rheumatologist. A 40-year-old hypertensive male with chronic alcoholism presented with one year duration of multiple ill- to well-defined, tender, erythematous to yellowish-white, slightly firm nodules of varying sizes over the dorsum of feet, lateral malleoli, and soles [Figure 1]. He also had a history of intermittent bilateral ankle pain with swelling. There were no urinary complaints or history of drugs. Dermoscopy revealed creamy-white, large structureless areas with surrounding violaceous erythema and linear vessels traversing the periphery of a few evolving lesions. Dermatoglyphics were maintained. Shiny yellow-white clods were visible in a few lesions representing the areas of impending discharge. White scales were also noted, signifying hyperkeratosis on top of the urate deposits [Figure 2]. Fine needle aspiration cytology of chalky white particulate matter expressed from the nodules showed needle-shaped crystals after Giemsa staining [Figure 3]. Plain radiographs of his feet showed reduced joint space without any erosions or radio-dense deposits.Figure 1: Multiple ill- to well-defined, erythematous to yellowish-white nodules of varying sizes over the dorsum of feet, lateral malleoli, and solesFigure 2: Creamy-white, large structureless areas with surrounding violaceous erythema and linear vessels traversing the periphery of a few evolving lesions. Dermatoglyphics were maintained. Shiny yellow-white clods were visible in a few lesions representing the areas of impending discharge (Dermlite4, 10x)Figure 3: Giemsa-stained smear at 100 × magnification of the aspirate showing needle-shaped crystals of mono-sodium urate on a light microscopeInvestigations revealed elevated serum uric acid (7.5 mg/dl) and serum creatinine (1.3 mg/dL) with an estimated glomerular filtration rate (GFR) of 47.5 ml/min/body surface area. His serum calcium, phosphate, and parathormone levels were normal. Ultrasound of the urinary system revealed a 9 mm calculus in the upper calyx of his left kidney. A diagnosis of tophaceous gout was made, and he was started on urate lowering therapy (ULT) in the form of allopurinol in a renal modified dose of 50 mg once daily along with telmisartan for hypertension. Tophi can rarely occur as the first manifestation of gout in the absence of arthritis due to deposition of monosodium urate crystals in subcutaneous tissues.[1] The usual sites of tophi formation are around interphalangeal joints and the olecranon process but can rarely occur elsewhere including kidneys.[1] The risk factors for the development of chronic tophaceous gout are male gender, hypertension, chronic renal insufficiency, alcoholism, use of drugs like thiazides and aspirin, and lack of early institution of ULT.[2] Such patients should be evaluated for biochemical abnormalities in renal function, serum calcium, parathormone levels, uric acid, and C-reactive protein. Radiological evaluation can demonstrate joint involvement and aid in differentiation from calcinosis as urate crystals are translucent. Smear analysis of aspirate from tophi can yield negatively birefringent needle-shaped crystals on polarized microscopy. Non-invasive tools like dermoscopy may be helpful in initial differentiation from other causes like rheumatoid nodules and calcinosis cutis.[3] Rheumatoid nodules show a pink homogeneous background with dull orange areas signifying areas of granulomatous inflammation, while the latter is more firm to hard, well-defined and looks chalky white on dermoscopy with minimal surrounding inflammation. According to the American College of Rheumatology,[4] ULT must be initiated for tophi. Allopurinol is the preferred ULT, including chronic kidney disease (CKD) stage >3 to maintain uric acid levels below 6 mg/dl. Lifestyle measures, control of hypertension with non-thiazide agents (particularly uricosuric agents like angiotensin receptor blockers), dietary restriction of purines, and avoidance of alcohol should be instituted. The above case highlights that atypical papules and nodules over the sole of feet can be the first manifestation of gout and various bedside tests like dermoscopy and Giemsa smear from aspirate can help establish the early diagnosis. To conclude, recognizing tophaceous gout in the absence of arthritis can be aided by dermoscopy in appropriate clinical settings and helps in early rheumatology referral and institution of ULT. Author contributions Manuscript has been read and approved by all the authors, and each author believes that the manuscript represents honest work. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.