Tophi in gout: what they are and how to treat them

Tophi are dense nodules of monosodium urate crystals that form in soft tissue, cartilage, bone, tendons, and around joints due to long-term hyperuricemia. They reflect the chronic course of gout and arise from a long-term imbalance between uric acid production and excretion. Over time, the crystals coalesce into conglomerates, around which granulomatous inflammation develops, forming a clinically noticeable nodule. [1]

Classic sites of localization include the first metatarsophalangeal joint of the foot, the Achilles tendon, the olecranon bursa, the auricle, the fingers, and the extensor surfaces. Tophi are often multiple and asymmetrical, and can be located intraosseously or within tendons. Externally, they appear as dense, painless or moderately painful, lumpy formations, sometimes with translucent whitish fluid and areas of vascularization of the skin. [2]

The clinical significance of tophi extends beyond their cosmetic appearance. They promote chronic inflammation, accelerate erosive changes in bone and cartilage, limit joint mobility, and can lead to nerve and tendon compression. Cases of median nerve compression syndrome, requiring urgent decompression, have been reported in cases of tophi located in the carpal tunnel. [3]

Increased tophi formation is a sign of severe gout. International guidelines consider the presence of tophi as an absolute indication for initiating uric acid-lowering therapy with a lower target uric acid concentration compared to the non-tophi form of the disease. [4]

How tophi form: pathogenesis and complications

The key trigger is prolonged uric acid concentrations above the solubility threshold, causing crystals to precipitate in the tissues and activating inflammation. Granulomatous tissue with macrophages and giant cells forms around the crystals, stabilizing the nodule and making it resistant to spontaneous resorption without a decrease in urate levels. Against this background, even minor fluctuations in urate levels and local microtrauma maintain chronic activity of the process. [5]

Complications include bone erosions, tendon ruptures, joint stiffness, chronic ulcers from skin ulceration over the tophus, and secondary infection. If localized in the carpal tunnel or near nerves, compression neuropathy is possible. Radiculopathy and myelopathy, requiring surgical intervention, have been described with spinal involvement. [6]

The risk of complications increases with long-term uncontrolled hyperuricemia, chronic kidney disease, diuretic abuse, and the combination of obesity, metabolic syndrome, and hypertension. These factors simultaneously increase crystal formation and impair their elimination. Managing risk factors accelerates tophi regression during therapy. [7]

Table 1. Typical locations and clinical manifestations of tophi

Localization	What can be seen and felt	Possible consequences
First metatarsophalangeal joint, Achilles tendon	Dense nodes, local pain, skin tension	Erosions, limited range of motion
Ulnar bursa, extensors of the fingers	Lumpy, painless nodules	Bursitis, ulceration
Carpal tunnel, tendons of the hand	Edema, paresthesia, weakness of grip	Median nerve compression syndrome
Spine, costovertebral joints	Pain, neurological deficit	Radiculopathy, need for surgery

When to see a doctor and what red flags to look out for

Reasons for an urgent visit include rapidly growing nodes, ulceration or oozing over them, signs of soft tissue infection, severe pain or numbness in the hand and wrist, weakness of the hand or foot, and symptoms of nerve compression. These situations require an assessment for compression of neurovascular structures and a decision on emergency surgical care. [8]

Even with stable nodules, routine examination is necessary if attacks become more frequent, the number of tophi increases, mobility deteriorates, or chronic kidney disease is newly diagnosed. These circumstances change treatment priorities, including more aggressive urate-lowering strategies and early transition to second-line drugs. [9]

Patients on diuretics require special attention. These medications increase the risk of gout and complicate disease control. If possible, it is advisable to discuss alternatives and adjust concomitant therapy. [10]

Diagnostics: clinical examination, puncture, laboratory

Clinical diagnosis relies on visible or palpable nodules in typical locations and a history of gout. However, definitive confirmation is achieved by detecting needle-shaped, negatively birefringent monosodium urate crystals in a tophus aspirate or synovial fluid under a polarizing microscope. This remains the "gold standard." [11]

Serum uric acid is helpful in assessment, but its level may be normal between attacks or fluctuate during therapy. Therefore, classification criteria take into account a complex of features, with crystals and visualization of specific deposits being crucial. [12]

The 2015 American College of Rheumatology/European League Against Rheumatism criteria allow for clinical tophus to be included as one of the criteria and also utilize imaging data—a "double contour" on ultrasound or urate accumulation on dual-energy computed tomography. This improves diagnostic accuracy when puncture is not possible. [13]

Instrumental visualization of tophi

Ultrasound examination reveals a typical "double contour"—a hyperechoic rim on the cartilage surface—as well as tophi themselves as heterogeneous formations with acoustic artifacts. Dynamic assessment of this feature helps differentiate gout from calcium pyrophosphate arthropathy. The method is accessible, safe, and suitable for monitoring. [14]

Dual-energy computed tomography (DECT) specifically stains and quantifies the volume of urate deposits. This is useful for complex anatomy, deep-seated nodules, and for monitoring tophi regression during treatment. Modern reconstructions reduce noise and radiation dose, while increasing contrast and sensitivity. [15]

Radiography is useful for detecting erosions but is less sensitive to soft tissue deposits. Magnetic resonance imaging is used when indicated for atypical locations, nerve compression, or suspected alternative pathology. The choice of method is dictated by the clinical objective. [16]

Table 2. Imaging for gout with tophi: when which method is appropriate

Method	Strengths	Restrictions	Typical indications
Ultrasound examination	Accessibility, no radiation exposure, double-circuit monitoring	Operator-dependent method	Confirmation of crystalline deposits, monitoring of dynamics
Dual-energy computed tomography	Specific visualization of urates, quantitative assessment	Cost, radiation exposure	Complex anatomy, hidden tophi, volumetric monitoring
X-ray	Erosions and chronic changes	Low sensitivity to soft tissues	Basic assessment of bone lesions

Treatment goals

The basic principle is to reduce uric acid to below 6 mg/dL for most patients and below 5 mg/dL in severe cases with tophi, frequent attacks, or chronic arthropathy. This approach accelerates crystal dissolution and leads to gradual reduction and disappearance of tophi. [17]

It is recommended to titrate the urate-lowering drug dose to achieve the target, with regular monitoring of urates every 2-4 weeks during the dose adjustment period and then at least once every 6-12 months during stable remission. For patients with tophi, it is advisable to monitor more frequently until visual regression is observed. [18]

When initiating urate-lowering therapy, it is important to prophylactically suppress attacks with anti-inflammatory drugs. It is recommended to continue prophylaxis for at least 3-6 months with subsequent reassessment, as premature discontinuation is associated with relapses. [19]

Table 3. Goals and monitoring for tophaceous gout

Parameter	Recommendation	Justification
The purpose of uric acid	Less than 6 mg per deciliter; with tophi less than 5 mg per deciliter	Faster dissolution of crystals
Frequency of urate monitoring	Every 2-4 weeks until goal is reached, then once every 6-12 months	Implementing the "reach and retain" strategy
Prevention of attacks	At least 3-6 months from the start of urate-lowering therapy	Reduction in the frequency of exacerbations due to crystal mobilization

Non-drug measures to accelerate the regression of tophi

Weight loss, blood pressure management, avoiding excess alcohol, and optimizing carbohydrate and fat intake reduce urate load and improve response to therapy. This is especially important in metabolic syndrome and chronic kidney disease. [20]

Reviewing concomitant medications is important: diuretics that increase urate levels should be avoided whenever possible, and alternatives should be chosen. This step contributes to achieving target uric acid levels and reduces the risk of new tophi. [21]

Adequate hydration and control of skin infections around ulcerated tophi reduce the risk of local complications. If signs of infection are present, early antibiotic therapy and consideration of surgical debridement are required. [22]

Table 4. Lifestyle and associated factors in tophaceous gout

Factor	What to change	Expected effect
Body weight and diet	Calorie deficit, reduction of sugar and alcohol	Decreased urates, less frequent attacks
Diuretics	Replace with alternatives if possible	Less hyperuricemia
Hydration and skin care	Adequate drinking, sanitation of foci	Fewer ulcers and infections

Drug Therapy: What Works for Tophi

First-line drugs are xanthine oxidase inhibitors. Allopurinol is started at low doses and titrated gradually to the target. This is a basic, effective, and affordable option, also suitable for chronic kidney disease with an appropriate starting dose and titration steps. [23]

Febuxostat is an alternative xanthine oxidase inhibitor for patients intolerant to or with inadequate efficacy of allopurinol. Data from a large prospective study demonstrated comparable cardiovascular safety to allopurinol during long-term follow-up, allaying some of the previous concerns. [24]

Uricosuric agents such as probenecid and benzbromarone enhance renal urate excretion and are used as an alternative or in combination with xanthine oxidase inhibitors when monotherapy is insufficient. The combination allows for more reliable achievement of target urate levels, especially in cases of severe hyperuricemia. The choice is limited by availability and safety profile. [25]

In refractory tophaceous gout, when goals are not achieved despite combination therapy and risk factor correction, uricase is used. The combination of pegloticase with the immunomodulator methotrexate increases the rate of sustained response, reduces the risk of infusion reactions, and accelerates tophi reduction, according to one-year follow-up data. [26]

In parallel, during the first months of urate-lowering therapy, prophylaxis against attacks with colchicine, nonsteroidal anti-inflammatory drugs, or glucocorticoids in low doses is prescribed for at least 3-6 months, with subsequent reassessment. This reduces the "paradox" of exacerbations due to crystal mobilization. [27]

Table 5. Medicines for tophaceous gout: place in therapy and control

Class	Role in tophi	Titration and control practice	Notes
Allopurinol	First line for lowering urates	Gradually increase the dose to the target, control urates	Acceptable in chronic kidney disease with dose adjustment
Febuxostat	Alternative in case of intolerance or lack of effect	Titration under urate control	Safety data comparable to allopurinol in long-term follow-up
Probenecid, benzbromarone	Uricosurics as mono or in combination	Assessment of kidney function, risk of nephrolithiasis	The combination helps to achieve the goal of urates
Pegloticase with methotrexate	Refractory tophaceous gout	Infusions according to the schedule, prevention of attacks	Higher response rate and regression of tophi within 6-12 months
Prevention of attacks	Supporting the initiation of urate-lowering therapy	At least 3-6 months	Reduces the frequency of exacerbations at the start of treatment

Local treatment and when surgery is needed

For ulcerated tophi, dressings, debridement, infection treatment, and pressure relief are indicated. If the nodules interfere with footwear or daily activities, limit movement, frequently become infected, or cause nerve compression, surgical removal is considered. The choice of technique depends on the location and size. [28]

Surgical treatment reduces pain, restores function, and facilitates skin care, but is associated with a risk of wound complications and requires close monitoring of urate levels before and after surgery. Modern techniques, including gentle "shaver" treatment, yield better results when performed electively before the node becomes infected. [29]

Indications for surgery are formulated individually: deformity and severe pain, limited function, recurrent ulcers, recurrent infections, rapid node enlargement, and nerve or tendon compression. The decision is made jointly with the rheumatologist and surgeon, taking into account urate monitoring and overall risk. [30]

Table 6. Tophi surgery: when, how, and what are the risks?

Situation	What are they doing?	Main risks	Comment
Nerve compression, severe pain, deformity	Tophus removal, decompression	Delayed healing, infection	Better outcomes with good urate control
Frequent ulcers and infections	Radical or gentle treatment, shaver technique	Wound complications	Planned surgery is preferable to interventions "during" infection

Observation and objectification of tophi regression

In addition to clinical examination, tophi regression can be monitored instrumentally. Dual-energy computed tomography allows for quantitative assessment of the volume of urate deposits and their dynamics against the background of declining urate levels. This is useful for multiple deep nodules and in research practice. [31]

Ultrasound examination helps to document the disappearance of the "double contour," a reduction in the size of tophi, and inflammatory signs. This is a low-cost monitoring method available in outpatient practice. [32]

A clear correlation between maintaining target uric acid levels and reducing crystal volume has been confirmed across various imaging modalities, supporting a "target-and-maintain" strategy as the basis for long-term remission. [33]

Frequently asked questions

Is it possible to "dissolve" existing tophi without surgery?
Yes. By consistently maintaining uric acid levels below the target, the crystals gradually dissolve, and the nodules shrink and may disappear completely. The timeframe varies from person to person and depends on the size, location, and initial urate levels. [34]

How often should uric acid levels be checked during the dose selection phase?
Ideally, every 2-4 weeks until the target is reached, then once every 6-12 months if the disease is stable. For large tophi, monitoring may be more frequent until significant regression occurs. [35]

If allopurinol doesn't help, what next?
Potential options include increasing the dose under safety monitoring, switching to febuxostat, or adding a uricosuric agent or uricase in refractory disease. The choice depends on the underlying pathology and tolerability. [36]

When to consider surgery?
When tophi ulcerate, frequently become infected, grow rapidly, limit movement, interfere with shoeing, or cause pain or neurological symptoms. Elective surgery with good urate control yields the best outcomes. [37]