Plasmapheresis may be used to decrease viscosity in the case of myeloma, whereas leukapheresis or phlebotomy may be employed in a leukemic or polycythemic crisis, respectively. Blood transfusions should be used with caution as they can increase serum viscosity. Hydration is a temporizing measure to employ while preparing pheresis. Even after treatment, the condition will recur unless the underlying disorder is treated.

The second stage features the reabsorption of the initially extravasated fluid and albumin from the tissues, and it usually lasts 1 to 2 days. Intravascular fluid overload leads to polyuria and can cause flash pulmonary edema and cardiac arrest, with possibly fatal consequences. Death from SCLS typically occurs during this recruitment phase because of pulmonary edema arising from excessive intravenous fluid administration during the earlier leak phase. The severity of the problem depends on to the quantity of fluid supplied in the initial phase, the damage that may have been sustained by the kidneys, and the promptness with which diuretics are administered to help the patient discharge the accumulated fluids quickly. A recent study of 59 acute episodes occurring in 37 hospitalized SCLS patients concluded that high-volume fluid therapy was independently associated with poorer clinical outcomes, and that the main complications of SCLS episodes were recovery-phase pulmonary edema (24%), cardiac arrhythmia (24%), compartment syndrome (20%), and acquired infections (19%).

The prevention of episodes of SCLS has involved two approaches. The first has long been identified with the Mayo Clinic, and it recommended treatment with beta agonists such as terbutaline, phosphodiesterase-inhibitor theophylline, and leukotriene-receptor antagonists montelukast sodium.

The rationale for use of these drugs was their ability to increase intracellular cyclic AMP (adenosine monophosphate) levels, which might counteract inflammatory signaling pathways that induce endothelial permeability. It was the standard of care until the early 2000s, but was sidelined afterwards because patients frequently experienced renewed episodes of SCLS, and because these drugs were poorly tolerated due to their unpleasant side effects.

The second, more recent approach pioneered in France during the last decade (early 2000s) involves monthly intravenous infusions of immunoglobulins (IVIG), with an initial dose of 2 gr/kg/month of body weight, which has proven very successful as per abundant case-report evidence from around the world.

IVIG has long been used for the treatment of autoimmune and MGUS-associated syndromes, because of its potential immunomodulatory and anticytokine properties. The precise mechanism of action of IVIG in patients with SCLS is unknown, but it is likely that it neutralizes their proinflammatory cytokines that provoke endothelial dysfunction. A recent review of clinical experience with 69 mostly European SCLS patients found that preventive treatment with IVIG was the strongest factor associated with their survival, such that an IVIG therapy should be the first-line preventive agent for SCLS patients. According to a recent NIH survey of patient experience, IVIG prophylaxis is associated with a dramatic reduction in the occurrence of SCLS episodes in most patients, with minimal side effects, such that it may be considered as frontline therapy for those with a clear-cut diagnosis of SCLS and a history of recurrent episodes.

The initial stage is the capillary leak phase, lasting from 1 to 3 days, during which up to 70% of total plasma volume may invade cavities especially in the extremities. The most common clinical features are flu-like symptoms such as fatigue; runny nose; lightheadedness up to and including syncope (fainting); limb, abdominal or generalized pain; facial or other edema; dyspnea; and hypotension that results in circulatory shock and potentially in cardiopulmonary collapse and other organ distress or damage. Acute renal dysfunction or failure is a common risk due to acute tubular necrosis consequent to hypovolemia and rhabdomyolysis.

The loss of fluid out of the capillaries has similar effects on the circulation as dehydration, slowing both the flow of oxygen delivered to tissues and organs as well as the output of urine. Urgent medical attention in this phase consists of fluid resuscitation efforts, mainly the intravenous administration of saline solution plus hetastarch or albumin and colloids (to increase the remaining blood flow to vital organs like the kidneys), as well as glucocorticoids (steroids like methylprednisolone, to reduce or stop the capillary leak). However effective on blood pressure, the impact of fluid therapy is always transient and leads to increased extravascular fluid accumulation, engendering multiple complications especially compartment syndrome and thus limb-destructive rhabdomyolysis. Consequently, patients experiencing episodes of SCLS should be closely monitored in a hospital intensive-care setting, including for orthopedic complications requiring surgical decompression, and their fluid therapy should be minimized as much as possible.

Treatment of mixed cryoglobulinemic disease is, similar to type I disease, directed toward treating any underlying disorder. This includes malignant (particularly Waldenström's macroglobulinemia in type II disease), infectious, or autoimmune diseases in type II and III disease. Recently, evidence of hepatitis C infection has been reported in the majority of mixed disease cases with rates being 70-90% in areas with high incidences of hepatitis C. The most effective therapy for hepatitis C-associated cryoglobulinemic disease consists of a combination of anti-viral drugs, pegylated INFα and ribavirin; depletion of B cells using rituximab in combination with antiviral therapy or used alone in patients refractory to antiviral therapy has also proven successful in treating the hepatitis C-associated disease. Data on the treatment of infectious causes other than hepatitis C for the mixed disease are limited. A current recommendation treats the underlying disease with appropriate antiviral, anti-bacterial, or anti-fungal agents, if available; in cases refractory to an appropriate drug, the addition of immunosuppressive drugs to the therapeutic regimen may improve results. Mixed cryoglobulinemic disease associated with autoimmune disorders is treated with immunosuppressive drugs: combination of a corticosteroid with either cyclophosphamide, azathioprine, or mycophenolate or combination of a corticosteroid with rituximab have been used successfully to treated mixed disease associated with autoimmune disorders.

Although elevated whole blood viscosity is a better measure of hyperviscosity and more common and clinically important, serum viscosity and plasma viscosity are more frequently measured. Normal plasma viscosity is between 1.4 and 1.8 centipoise while symptoms from hyperviscosity typically occur greater than 4 centipoise (about 4 times more viscous than water) and require emergency treatment.

Patients will also have evidence of their underlying disorder. Those with myeloma will typically display a rouleaux formation on a peripheral smear and a large globulin gap, indicative of a significant paraprotein load. While viscosity can be directly measured, results can take a few days to return and thus a high index of suspicion is required to make the diagnosis in a timely manner. If hyperviscosity is suspected, treatment may need to be started prior to obtaining the official viscosity level.

People affected by the severest, often life-threatening, complications of cryoglobulinemic disease require urgent plasmapharesis and/or plasma exchange in order to rapidly reduce the circulating levels of their cryoglobulins. Complications commonly requiring this intervention include: hyperviscosity disease with severe symptoms of neurological (e.g. stroke, mental impairment, and myelitis) and/or cardiovascular (e.g., congestive heart failure, myocardial infarction) disturbances; vasculitis-driven intestinal ischemia, intestinal perforation, cholecystitis, or pancreatitis, causing acute abdominal pain, general malaise, fever, and/or bloody bowel movements; vasculitis-driven pulmonary disturbances (e.g. coughing up blood, acute respiratory failure, X-ray evidence of diffuse pulmonary infiltrates caused by diffuse alveolar hemorrhage); and severe kidney dysfunction due to intravascular deposition of immunoglobulins or vasculitis. Along with this urgent treatment, severely symptomatic patients are commonly started on therapy to treat any underlying disease; this treatment is often supplemented with anti-inflammatory drugs such as corticosteroids (e.g., dexamethasone) and/or immunosuppressive drugs. Cases where no underlying disease is known are also often treated with the latter corticosteroid and immunosuppressive medications.

Cilostazol or pentoxifylline can improve symptoms in some. Cilostazol may improve walking distance for people who experience claudication due to peripheral artery disease, but there is no strong evidence to suggest that it improves the quality of life, decreases mortality, or decreases the risk of cardiovascular events.

Treatment with other drugs or vitamins are unsupported by clinical evidence, "but trials evaluating the effect of folate and vitamin B-12 on hyperhomocysteinemia, a putative vascular risk factor, are near completion".

Antihistamines are not effective in treating the hives in this condition. It may respond to immunosuppressant drugs such as corticosteroids, cyclooxygenase inhibitors, interferon alpha, interleukin 1 receptor antagonists (Anakinra), perfloxacin, colchicine, cyclosporine or thalidomide. The hives may respond to treatment with PUVA, and the bone pain may respond to bisphosphonates.

Because Schnitzler's syndrome is so rare, the efficacy of different treatments cannot be compared using statistics. Nevertheless, case studies provide evidence that anakinra (otherwise known as kineret) is much more effective for Schnitzler's syndrome than any other drug, and that the improvement in symptoms associated with this treatment is dramatic. For example, Beseda and Nossent (2010) reviewed the literature concerning IL1-RA treatment (i.e. anakinra) for Schnitzler's syndrome. They concluded that, “Twenty-four patients with Schnitzler's syndrome... have been successfully treated with anakinra.” They add that “seven out of seven patients [with Schnitzler’s syndrome], that either interrupted or used anakinra every other day, had relapse of their symptoms within 24-48 h; anakinra was restarted in all patients with the same clinical efficiency.” Kluger et al. (2008) investigated the effectiveness of anakinra for a range of conditions. They searched MEDLINE for English-language trials of anakinra and abstracts from rheumatologial scientific meetings. They conclude that, “Over the last few years it has become increasingly evident that anakinra is highly effective and safe in patients with ... Schnitzler’s syndrome”. The year before, De Koning et al. (2007) reviewed the disease characteristics of Schnitzler syndrome and collected follow-up information to gain insight into long-term prognosis and treatment efficacy. They used data from 94 patients, and their conclusions about treatment for the condition are that, “There have been promising developments in therapeutic options, especially antiinterleukin-1 treatment, which induced complete remission in all 8 patients treated so far.”

Reports of individual patients treated with anakinra illustrate its effectiveness. Beseda and Nossent (ibid.) report treating a longstanding multidrug resistant Schnitzler’s syndrome patient with anakinra: “Within 24 h after the first injection, both the urticaria and the fever disappeared and have not recurred. For the past 6 months, the patient has been in clinical and biochemical remission.” Other authors report “a complete resolution of symptoms” (Dybowski et al., 2008). Crouch et al. (2007) report the effective treatment of a 52-year-old man who had been diagnosed with Schnitzler’s syndrome 8 years earlier: “On review, one week later, the patient’s systemic symptoms had resolved, and his previously elevated white cell count and inflammatory markers had normalised. The use of anakinra in our patient resulted in resolution of symptoms and has enabled cessation of oral prednisolone. Our patient remains symptom free on anakinra after 14 months of follow-up”. Similar stories are reported by Frischmeyer-Guerrerio et al. (2008), Wastiaux et al. (2007), and Eiling et al. (2007), Schneider et al. (2007). De Koning et al. (2006) treated three patients with Schnitzler’s syndrome with thalidomide and anakinra. Thalidomide was only effective for one of the three patients and was discontinued because of polyneuropathy. In contrast, for all three patients, anakinra “led to disappearance of fever and skin lesions within 24 hours. After a follow-up of 16-18 months, all patients are free of symptoms”. The authors concluded that anakinra as a treatment for Schnitzler’s syndrome “is preferable to thalidomide... as it has fewer side effects”.

As well as being more effective, anakinra is safer than the other treatments available for Schnitzler's syndrome. The Cochrane review entitled, ‘Anakinra for rheumatoid arthritis’ (Mertens and Singh, 2009 ) evaluates the (clinical effectiveness and) safety of anakinra in adult patients with rheumatoid arthritis, using data from 2876 patients, from five trials which constituted 781 randomized to placebo and 2065 to anakinra. The authors conclude, “There were no statistically significant differences noted in most safety outcomes with treatment with anakinra versus placebo - including number of withdrawals, deaths, adverse events (total and serious), and infections (total and serious). Injection site reactions were significantly increased, occurring in 1235/1729 (71%) versus 204/729 (28%) of patients treated with anakinra versus placebo, respectively”. These injection site reactions last for no more than four months, and are trivial compared to the very debilitating symptoms of Schnitzler's syndrome.

After a trial of the best medical treatment outline above, if symptoms persist, patients may be referred to a vascular or endovascular surgeon. The benefit of revascularization is thought to correspond to the severity of ischemia and the presence of other risk factors for limb loss such as wound and infection severity.

- Angioplasty (PTA, or percutaneous transluminal angioplasty) can be done on solitary lesions in large arteries, such as the femoral artery, but angioplasty may not have sustained benefits. Patency rates following angioplasty are highest for iliac arteries, and decrease with arteries towards the toes. Other criteria that affect outcome following revascularization are length of lesion, and number of lesions. There does not appear to be long term advantages or sustained benefit to placing a stent following angioplasty in order to hold the narrowing of the superficial femoral artery open.

- Atherectomy, in which the plaque is scraped off of the inside of the vessel wall (albeit with no better results than angioplasty).

- Vascular bypass grafting can be performed to circumvent a diseased area of the arterial vasculature. The great saphenous vein is used as a conduit if available, although artificial (Gore-Tex or PTFE) material is often used for long grafts when adequate venous conduit is unavailable.

- When gangrene has set in, amputation is required to prevent infected tissues from causing sepsis a life-threatening illness.

- Thrombolysis and thrombectomy are used in cases of arterial thrombosis or embolism.

Treatment of HHS begins with reestablishing tissue perfusion using intravenous fluids. People with HHS can be dehydrated by 8 to 12 liters. Attempts to correct this usually take place over 24 hours with initial rates of normal saline often in the range of 1 L/h for the first few hours or until the condition stabilizes.

Potassium replacement is often required as the metabolic problems are corrected. It is generally replaced at a rate 10 mEq per hour as long as there is adequate urinary output.

Treatment is based on the cause of the retinopathy and may include laser therapy to the retina. Laser photocoagulation therapy has been the standard treatment for many types of retinopathy. Evidence show that laser therapy is generally safe and improves visual symptoms in sickle cell and diabetic retinopathy. In recent years targeting the pathway controlling vessel growth or angiogenesis has been promising. Vascular endothelial growth factor (VEGF) seems to play a vital role in promoting neovascularization. Using anti-VEGF drugs (antibodies to sequester the growth factor), research have shown significant reduction in the extent of vessel outgrowth. Evidence supports the use of anti-VEGF antibodies, such as bevacizumab or pegaptanib, seems to improve outcomes when used in conjunction with laser therapy to treat retinopathy of prematurity. The evidence is poorer for treatment of diabetic retinopathy. Use of anti-VEGF drugs did not appear to improve outcomes when compared to standard laser therapy for diabetic retinopathy.

Should treatment be started it should address both the paraprotein level and the lymphocytic B-cells.

In 2002, a panel at the International Workshop on Waldenström's Macroglobulinemia agreed on criteria for the initiation of therapy. They recommended starting therapy in patients with constitutional symptoms such as recurrent fever, night sweats, fatigue due to anemia, weight loss, progressive symptomatic lymphadenopathy or spleen enlargement, and anemia due to bone marrow infiltration. Complications such as hyperviscosity syndrome, symptomatic sensorimotor peripheral neuropathy, systemic amyloidosis, kidney failure, or symptomatic cryoglobulinemia were also suggested as indications for therapy.

Treatment includes the monoclonal antibody rituximab, sometimes in combination with chemotherapeutic drugs such as chlorambucil, cyclophosphamide, or vincristine or with thalidomide. Corticosteroids, such as prednisone, may also be used in combination. Plasmapheresis can be used to treat the hyperviscosity syndrome by removing the paraprotein from the blood, although it does not address the underlying disease. Ibrutinib is another agent that has been approved for use in this condition.

Recently, autologous bone marrow transplantation has been added to the available treatment options.

Telemedicine programs are available that allow primary care clinics to take images using specially designed retinal imaging equipment which can then be shared electronically with specialists at other locations for review. In 2009, Community Health Center, Inc. implemented a telemedicine retinal screening program for low-income patients with diabetes as part of those patients annual visits at the Federally Qualified Health Center.

If the diagnostic workup reveals a systemic disease process, directed therapies to treat that underlying cause should be initiated. If the amaurosis fugax is caused by an atherosclerotic lesion, aspirin is indicated, and a carotid endarterectomy considered based on the location and grade of the stenosis. Generally, if the carotid artery is still patent, the greater the stenosis, the greater the indication for endarterectomy. "Amaurosis fugax appears to be a particularly favorable indication for carotid endarterectomy. Left untreated, this event carries a high risk of stroke; after carotid endarterectomy, which has a low operative risk, there is a very low postoperative stroke rate." However, the rate of subsequent stroke after amaurosis is significantly less than after a hemispheric TIA, therefore there remains debate as to the precise indications for which a carotid endarterectomy should be performed. If the full diagnostic workup is completely normal, patient observation is recommended.

When primary or secondary resistance invariably develops, salvage therapy is considered. Allogeneic stem cell transplantation can induce durable remissions for heavily pre-treated patients.

Relative polycythemia is an apparent rise of the erythrocyte level in the blood; however, the underlying cause is reduced blood plasma (hypovolemia, cf. dehydration). Relative polycythemia is often caused by loss of body fluids, such as through burns, dehydration, and stress. A specific type of relative polycythemia is Gaisböck syndrome. In this syndrome, primarily occurring in obese men, hypertension causes a reduction in plasma volume, resulting in (amongst other changes) a relative increase in red blood cell count.

The overproduction of red blood cells may be due to a primary process in the bone marrow (a so-called myeloproliferative syndrome), or it may be a reaction to chronically low oxygen levels or, rarely, a malignancy. Alternatively, additional red blood cells may have been received through another process—for example, being over-transfused (either accidentally or, as blood doping, deliberately) or being the recipient twin in a pregnancy, undergoing twin-to-twin transfusion syndrome.

The natural history of myeloma is of relapse following treatment. This may be attributed to tumor heterogeneity. Depending on the patient's condition, the prior treatment modalities used and the duration of remission, options for relapsed disease include re-treatment with the original agent, use of other agents (such as melphalan, cyclophosphamide, thalidomide or dexamethasone, alone or in combination), and a second autologous stem cell transplant.

Later in the course of the disease, "treatment resistance" occurs. This may be a reversible effect, and some new treatment modalities may re-sensitize the tumor to standard therapy. For patients with "relapsed disease", bortezomib is a recent addition to the therapeutic arsenal, especially as second line therapy, since 2005. Bortezomib is a proteasome inhibitor. Also, lenalidomide (Revlimid), a less toxic thalidomide analog, is showing promise for treating myeloma. The newly approved thalidomide derivative pomalidomide (Pomalyst in the U.S.) may be used for relapsed and refractory multiple myeloma.

In the 21st century, more patients have survived longer, as a result of stem cell transplant (with their own or a donor's) and treatments combining bortezomib (Velcade), dexamethasone and melphalan or cyclophosphamide. This seems to maintain the monoclonal peak at a reasonable level. Survival expectancy has risen. New treatments are under development.

Kidney failure in multiple myeloma can be acute (reversible) or chronic (irreversible). Acute kidney failure typically resolves when the calcium and paraprotein levels are brought under control. Treatment of chronic kidney failure is dependent on the type of kidney failure and may involve dialysis.

Several newer options are approved for the management of advanced disease:

- ixazomib — an orally available proteasome inhibitor indicated in combination with lenalidomide and dexamethasone in people who have received at least one prior therapy;

- panobinostat — an orally available histone deacetylase inhibitor used in combination with bortezomib and dexamethasone in people who have received at least 2 prior chemotherapy regimens, including bortezomib and an immunomodulatory agent (such as lenalidomide or pomalidomide);

- carfilzomib — a proteasome inhibitor that is indicated:

- as a single agent for the treatment of patients with relapsed or refractory multiple myeloma who have received one or more lines of therapy;

- in combination with dexamethasone or with lenalidomide+dexamethasone for the treatment of patients with relapsed or refractory multiple myeloma who have received one to three lines of therapy;

- elotuzumab — an immunostimulatory humanized monoclonal antibody against SLAMF7 (also known as CD319). It is FDA-approved for the treatment of patients who have received one to three prior therapies (in combination with lenalidomide and dexamethasone);

- daratumumab — a monoclonal antibody against CD38 indicated for the treatment of patients with multiple myeloma who have received at least three prior lines of therapy including a proteasome inhibitor and an immunomodulatory agent or who are double refractory to a proteasome inhibitor and an immunomodulatory agent.

Most people, including those treated with ASCT, will relapse after initial treatment. Maintenance therapy using a prolonged course of low toxicity medications is often used to prevent relapse. A 2017 meta-analysis showed that post ASCT maintenance therapy with lenalidomide improved progression free survival and overall survival in people at standard risk. A 2012 clinical trial showed that people with intermediate and high risk disease benefit from a bortezomib based maintenance regimen.

The first line treatment is change of lifestyle (e.g., Dietary Guidelines for Americans and physical activity). However, if in three to six months of efforts at remedying risk factors prove insufficient, then drug treatment is frequently required. Generally, the individual disorders that compose the metabolic syndrome are treated separately. Diuretics and ACE inhibitors may be used to treat hypertension. Cholesterol drugs may be used to lower LDL cholesterol and triglyceride levels, if they are elevated, and to raise HDL levels if they are low. Use of drugs that decrease insulin resistance, e.g., metformin and thiazolidinediones, is controversial; this treatment is not approved by the U.S. Food and Drug Administration. Weight loss medications may result in weight loss. As obesity is often recognized as the culprit behind many of the additional symptoms, with weight loss and lifestyle changes in diet, physical activity, the need for other medications may diminish.

A 2003 study indicated cardiovascular exercise was therapeutic in approximately 31% of cases. The most probable benefit was to triglyceride levels, with 43% showing improvement; but fasting plasma glucose and insulin resistance of 91% of test subjects did not improve.

Many other studies have supported the value of physical activity and dietary modifications to treat metabolic syndrome. Some natural compounds, like ursolic acid, have been suggested as a treatment for obesity/metabolic syndrome based on the results of extensive research involving animal models; it is argued, however, that there is still a lack of data regarding the use of ursolic acid in humans, as phase-II/III trials of that drug have not been carried so far.

Restricting the overall dietary carbohydrate intake is more effective in reducing the most common symptoms of metabolic syndrome than the more commonly prescribed reduction in dietary fat intake.

The combination preparation simvastatin/sitagliptin (marketed as Juvisync) was introduced in 2011 and the use of this drug was to lower LDL levels and as well as increase insulin levels. This drug could have been used to treat metabolic syndrome but was removed from the market by Merck in 2013 due to business reasons.

High-dose statins, recommended to reduce cardiovascular risk, have been associated with higher progression to diabetes, particularly in patients with metabolic syndrome. The biological mechanisms are not entirely understood, however, the plausible explanation may lie in competitive inhibition of glucose transport via the solute carrier (SLC) family of transporters (specifically "SLCO1B1"), important in statin pharmacokinetics.

Some studies on mice suggest that a Time Restricted Diet (TRD) could be helpful in reversing obesity and possibly metabolic syndrome

The life span in patients with Schnitzler syndrome has not been shown to differ much from the general population. Careful follow-up is advised, however. A significant proportion of patients develops a lymphoproliferative disorder as a complication, most commonly Waldenström's macroglobulinemia. This may lead to symptoms of hyperviscosity syndrome. AA amyloidosis has also been reported in people with Schnitzler syndrome.

Harlequin syndrome is not debilitating so treatment is not normally necessary. In cases where the individual may feel socially embarrassed, contralateral sympathectomy may be considered, although compensatory flushing and sweating of other parts of the body may occur. In contralateral sympathectomy, the nerve bundles that cause the flushing in the face are interrupted. This procedure causes both sides of the face to no longer flush or sweat. Since symptoms of Harlequin syndrome do not typically impair a person’s daily life, this treatment is only recommended if a person is very uncomfortable with the flushing and sweating associated with the syndrome.

Amaurosis fugax (Latin "" meaning "fleeting", Greek "" meaning "darkening", "dark", or "obscure") is a painless temporary loss of vision in one or both eyes.

In terms of treatment of oculocerebrorenal syndrome for those individuals who are affected by this condition includes the following:

- Glaucoma control (via medication)

- Nasogastric tube feeding

- Physical therapy

- Clomipramine

- Potassium citrate