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Acute Gout (Monosodium Urate Crystals)
Polarized light microscopy showing monosodium urate crystals. Note the negative birefringence (yellow) of needle-shaped crystals versus the rhomboid-shaped and positively birefringent (blue) crystals of crystal pyrophosphate disease (CPPD). (Courtesy Dr. A. Fam)
Acute Gouty Arthritis
Classic inflammation resembling cellulitis of the first metatarsophalangeal (MTP) joint, referred to as podagra. The first MTP is the most common site of initial involvement. (Courtesy Dr. A. Fam)
Prominent scaly fixed erythema, flat or raised over malar eminences, tending to spare nasolabial folds (“butterfly rash”).
Sclerodactyly showing bilateral swelling, a shiny wax-like appearance, and tapering of the fingers. May also note digital ulcers, nailfold telangiectasia, and periarticular calcinosis. Flexion contractures present in advanced disease. (Courtesy Dr. A. Fam)
Note subluxation of digits at the metacarpophalangeal (MCP) joints and rheumatoid nodules at 2nd and 3rd MCPs. (Courtesy of Dr. D. Jerome)
Significant ulnar deviation of the digits, typical of rheumatoid arthritis.
Note white discolouration of digits. (Courtesy of Dr. D. Jerome)
Onycholysis: Lifting of the nail starting at the distal end, seen in psoriatic arthritis. (Courtesy of Dr. D. Jerome)
Nail pitting seen in psoriatic arthritis. (Courtesy of Dr. D. Jerome)
Violaceous, hyperpigmented, atrophic plaques; keratotic scale with follicular plugging and scarring. (Courtesy Dr. L. From)
