The disease typically presents with joint pain, high fevers, a salmon-pink rash, enlargement of the liver and spleen, swollen lymph nodes, and an increased white blood cell count in the blood. Tests for rheumatoid factor and anti-nuclear antibodies are usually negative and serum ferritin is elevated. Patients experiencing a flare-up from Adult-onset Still's disease usually report extreme fatigue, swelling of the lymph nodes and, less commonly, fluid accumulation in the lungs and heart. In rare cases, AOSD can cause aseptic meningitis and sensorineural hearing loss.

Adult-onset Still's disease (AOSD) is a form of Still's disease, a rare systemic autoinflammatory disease characterized by the classic triad of persistent high spiking fevers, joint pain, and a distinctive salmon-colored bumpy rash. The disease is considered a diagnosis of exclusion. Levels of the iron-binding protein ferritin may be elevated with this disorder. AOSD may present in a similar manner to other inflammatory diseases and to autoimmune diseases, which must be ruled out before making the diagnosis.

Prognosis is usually favorable but manifestations of the disease affecting the lungs, heart, or kidneys may occasionally cause severe life-threatening complications. It is treated first with steroids such as prednisone. Drugs that block the action of interleukin-1, such as anakinra, can be effective treatments when standard steroid treatments are insufficient.

The most common symptoms are diarrhea, abdominal pain, weight loss, and joint pains. The joint pains may be due to migratory non-deforming arthritis, which may occur many years before any digestive tract symptoms develop; they tend to involve the large joints but can occur in any pattern and tend not to damage the joint surface to the point that the joint becomes deformed. Fever and chills occur in a small proportion of people.

In its more advanced form, malabsorption (insufficient absorption of nutrients from the diet) leads to wasting and the enlargement of lymph nodes in the abdomen. Neurological symptoms (discussed below) are more common in those with the severe form of the abdominal disease. Chronic malabsorptive diarrhea leads to the poor absorption of fat, causing steatorrhea (fatty, offensive stool), flatulence, and abdominal distension. Protein-losing enteropathy may also occur, causing depletion of albumin, a blood protein, which may lead to peripheral edema caused by the lowered oncotic pressures.

Hyperpigmentation of the skin occurs in almost half; some also have skin nodules. Various eye problems, such as uveitis, may occur; this is typically associated with deteriorating vision and pain in the affected eye. Endocarditis (infection of the heart valve) has been reported in a small number of cases, sometimes in people with no other symptoms of Whipple's disease; this is typically noticed as breathlessness and leg swelling due to fluid accumulation as the heart is unable to pump fluid through the body.

Of those affected by Whipple's disease, 10–40% of people have problems related to the involvement of the brain; the symptoms relate to the part of the brain that is affected. The most common problems are dementia, memory loss, confusion, and decreased level of consciousness. Eye movement disturbances and myorhythmia (rapidly repetitive movements of the muscles) of the face, together referred to as "oculomasticatory myorhythmia", are highly characteristic for Whipple's disease. Weakness and poor coordination of part of the body, headaches, seizures, as well as a number of more uncommon neurological features, are present in some cases.

The symptoms and signs of Bright's disease were first described in 1827 by the English physician Richard Bright, after whom the disease was named. In his "Reports of Medical Cases", he described 25 cases of dropsy (edema) which he attributed to kidney disease. Symptoms and signs included: inflammation of serous membranes, hemorrhages, apoplexy, convulsions, blindness and coma. Many of these cases were found to have albumin in their urine (detected by the spoon and candle-heat coagulation), and showed striking morbid changes of the kidneys at autopsy. The triad of dropsy, albumin in the urine and kidney disease came to be regarded as characteristic of Bright's disease. Subsequent work by Bright and others indicated an association with cardiac hypertrophy, which was attributed by Bright to stimulation of the heart. Subsequent work by Mahomed showed that a rise in blood pressure could precede the appearance of albumin in the urine, and the rise in blood pressure and increased resistance to flow was believed to explain the cardiac hypertrophy.

It is now known that Bright's disease is due to a wide range of diverse kidney diseases; thus, the term "Bright's disease" is retained strictly for historical application. The disease was diagnosed frequently in patients with diabetes; at least some of these cases would probably correspond to a modern diagnosis of diabetic nephropathy.

Crohn's disease, like many other chronic, inflammatory diseases, can cause a variety of systemic symptoms. Among children, growth failure is common. Many children are first diagnosed with Crohn's disease based on inability to maintain growth. As it may manifest at the time of the growth spurt in puberty, up to 30% of children with Crohn's disease may have retardation of growth. Fever may also be present, though fevers greater than 38.5 °C (101.3 °F) are uncommon unless there is a complication such as an abscess. Among older individuals, Crohn's disease may manifest as weight loss, usually related to decreased food intake, since individuals with intestinal symptoms from Crohn's disease often feel better when they do not eat and might lose their appetite. People with extensive small intestine disease may also have malabsorption of carbohydrates or lipids, which can further exacerbate weight loss.

Whipple's disease is a rare, systemic infectious disease caused by the bacterium "Tropheryma whipplei". First described by George Hoyt Whipple in 1907 and commonly considered a gastrointestinal disorder, Whipple's disease primarily causes malabsorption but may affect any part of the body including the heart, brain, joints, skin, lungs and the eyes. Weight loss, diarrhea, joint pain, and arthritis are common presenting symptoms, but the presentation can be highly variable and approximately 15% of patients do not have these classic signs and symptoms.

Whipple's disease is significantly more common in men, with 87% of the patients being male. When recognized and treated, Whipple's disease can usually be cured with long-term antibiotic therapy; if the disease is left untreated, it is ultimately fatal.

In addition to systemic and gastrointestinal involvement, Crohn's disease can affect many other organ systems. Inflammation of the interior portion of the eye, known as uveitis, can cause blurred vision and eye pain, especially when exposed to light (photophobia). Inflammation may also involve the white part of the eye (sclera), a condition called episcleritis. Both episcleritis and uveitis can lead to loss of vision if untreated.

Crohn's disease that affects the ileum may result in an increased risk for gallstones. This is due to a decrease in bile acid resorption in the ileum and the bile gets excreted in the stool. As a result, the cholesterol/bile ratio increases in the gallbladder, resulting in an increased risk for gallstones.

Crohn's disease is associated with a type of rheumatologic disease known as seronegative spondyloarthropathy. This group of diseases is characterized by inflammation of one or more joints (arthritis) or muscle insertions (enthesitis). The arthritis in Crohn's disease can be divided into two types. The first type affects larger weight-bearing joints such as the knee (most common), hips, shoulders, wrists, or elbows. The second type symmetrically involves five or more of the small joints of the hands and feet. The arthritis may also involve the spine, leading to ankylosing spondylitis if the entire spine is involved or simply sacroiliitis if only the sacroiliac joint is involved. The symptoms of arthritis include painful, warm, swollen, stiff joints, and loss of joint mobility or function.

Crohn's disease may also involve the skin, blood, and endocrine system. The most common type of skin manifestation, erythema nodosum, presents as raised, tender red nodules usually appearing on the shins. Erythema nodosum is due to inflammation of the underlying subcutaneous tissue, and is characterized by septal panniculitis. Another skin lesion, pyoderma gangrenosum, is typically a painful ulcerating nodule. Crohn's disease also increases the risk of blood clots; painful swelling of the lower legs can be a sign of deep venous thrombosis, while difficulty breathing may be a result of pulmonary embolism. Autoimmune hemolytic anemia, a condition in which the immune system attacks the red blood cells, is also more common in Crohn's disease and may cause fatigue, a pale appearance, and other symptoms common in anemia. Clubbing, a deformity of the ends of the fingers, may also be a result of Crohn's disease. Finally, Crohn's disease increases the risk of osteoporosis, or thinning of the bones. Individuals with osteoporosis are at increased risk of bone fractures.

People with Crohn's disease often have anemia due to vitamin B, folate, iron deficiency, or due to anemia of chronic disease. The most common is iron deficiency anemia from chronic blood loss, reduced dietary intake, and persistent inflammation leading to increased hepcidin levels, restricting iron absorption in the duodenum. As Crohn's disease most commonly affects the terminal ileum where the vitamin B12/intrinsic factor complex is absorbed, B12 deficiency may be seen. This is particularly common after surgery to remove the ileum. Involvement of the duodenum and jejunum can impair the absorption of many other nutrients including folate. If Crohn's disease affects the stomach, production of intrinsic factor can be reduced.

Crohn's disease can also cause neurological complications (reportedly in up to 15%). The most common of these are seizures, stroke, myopathy, peripheral neuropathy, headache and depression.

People with Crohn's often also have issues with small bowel bacterial overgrowth syndrome, which has similar symptoms.

In the oral cavity people with Crohn's may develop cheilitis granulomatosa and other forms of orofacial granulomatosis, pyostomatitis vegetans, recurrent aphthous stomatitis, geographic tongue, and migratory stomatitis in higher prevalence than the general population.

Inflammatory eye disease can develop early in the disease course and lead to permanent vision loss in 20 percent of cases. Ocular involvement can be in the form of posterior uveitis, anterior uveitis, or retinal vasculitis. Anterior uveitis presents with painful eyes, conjuctival redness, hypopyon, and decreased visual acuity, while posterior uveitis presents with painless decreased visual acuity and visual field floaters. A rare form of ocular (eye) involvement in this syndrome is retinal vasculitis which presents with painless decrease of vision with the possibility of floaters or visual field defects.

Optic nerve involvement in Behçet's disease is rare, typically presenting as progressive optic atrophy and visual loss. However, cases of acute optic neuropathy (specifically anterior ischemic optic neuropathy) have also been reported to occur. Optic nerve atrophy has been identified as the most common cause of visual impairment. Behçet's disease may result in primary or secondary optic nerve involvement. Papilledema as a result of dural sinus thrombosis and atrophy resulting from retinal disease, have been characterized as secondary causes of optic nerve atrophy in Behçet's disease.

Signs and symptoms of acute optic neuropathy include painless loss of vision which may affect either one or both eyes, reduced visual acuity, reduced color vision, relative afferent pupillary defect, central scotoma, swollen optic disc, macular edema, or retrobulbar pain. When these symptoms occur with concurrent mucocutaneous ulcerations, they raise suspicion of acute optic neuropathy in Behçet's Disease. Progressive optic atrophy may result in decreased visual acuity or color vision. Intracranial hypertension with papilledema may be present.

Arthralgia is seen in up to half of people, and is usually a non-erosive poly or oligoarthritis primarily of the large joints of the lower extremities.

Bright's disease is a historical classification of kidney diseases that would be described in modern medicine as acute or chronic nephritis. It was characterized by swelling, the presence of albumin in the urine and was frequently accompanied by high blood pressure and heart disease.

Ten (of 75) young patients had neurologic findings such as febrile seizures, single generalized seizures, mild ataxia, and muscular hypotonia with retarded motor development, but magnetic resonance imaging detected unilateral and bilateral T2-hyperintensive white-matter lesions in 15 patients (20%)

According to recent studies, calcifications of channels seen in dementia can also occur in specific brain areas such as the visual complex in the occipital lobe. Such calcium channel blockages can cause visual problems or partial field hallucinations (Paroxysmal visual manifestations). Other papers show a link between migraine, visual aura and cerebral calcifications. Disturbances may be followed by

convulsions and associated with gastrointestinal phenomena.

Systemic-onset juvenile idiopathic arthritis (also known as systemic juvenile idiopathic arthritis (sJIA) or the juvenile onset form of Still's disease) is a type of juvenile idiopathic arthritis (JIA) with extra-articular manifestations like fever and rash apart from arthritis. It was originally called systemic-onset juvenile rheumatoid arthritis or Still's disease.

Predominantly extra-articular manifestations like high fevers, rheumatic rash, enlargement of the liver and spleen, enlargement of the lymph nodes, and anemia. Others manifestations include inflammation of the pleura, inflammation of the pericardium, inflammation of the heart's muscular tissue, and inflammation of the peritoneum are also seen.

It is sometimes called "juvenile-onset Still's disease", to distinguish it from adult-onset Still's disease. However, there is some evidence that the two conditions are closely related.

Systemic JIA is characterized by arthritis, fever, which typically is higher than the low-grade fever associated with polyarticular and a salmon pink rash. It accounts for 10-20% of JIA and affects males and females equally, unlike the other two subtypes of JIA, and affects adolescents. It generally involves both large and small joints. Systemic JIA can be challenging to diagnose because the fever and rash come and go. Fever can occur at the same time every day or twice a day (often in late afternoon or evening) with a spontaneous rapid return to baseline (vs. septic arthritis of continuous fever). The rash often occurs with fever. It is a discrete, salmon-pink macules of different sizes. It migrates to different locations on skin, rarely persisting in one location more than one hour. The rash is commonly seen on trunk and proximal extremities or over pressure areas.

Arthritis is often absent in the first weeks or even 6–8 months into the illness.

Systemic JIA may have internal organ involvement such as hepatosplenomegaly, lymphadenopathy, serositis, hepatitis, or tenosynovitis.

A polymorphism in macrophage migration inhibitory factor has been associated with this condition.

A symptom complex characterised by the clinical features of a high intermittent fever of septic type, constantly recurring exanthema, transient arthralgia, carditis, pleurisy, neutrophil leukocytosis, and increased erythrocyte sedimentation rate.

Pogosta disease is a viral disease, established to be identical with other diseases, Karelian fever and Ockelbo disease. The names are derived from the words Pogosta, Karelia and Ockelbo, respectively.

The symptoms of the disease include usually rash, as well as mild fever and other flu-like symptoms; in most cases the symptoms last less than 5 days. However, in some cases, the patients develop a painful arthritis. There are no known chemical agents available to treat the disease.

It has long been suspected that the disease is caused by a Sindbis-like virus, a positive-stranded RNA virus belonging to the Alphavirus genus and family Togaviridae. In 2002 a strain of Sindbis was isolated from patients during an outbreak of the Pogosta disease in Finland, confirming the hypothesis.

This disease is mainly found in the Eastern parts of Finland; a typical Pogosta disease patient is a middle-aged person who has been infected through a mosquito bite while picking berries in the autumn. The prevalence of the disease is about 100 diagnosed cases every year, with larger outbreaks occurring in 7-year intervals.

Full body or localized pain to the extremities (known as acroparesthesia) or gastrointestinal (GI) tract is common in patients with Fabry disease. This acroparesthesia is believed to be related to the damage of peripheral nerve fibers that transmit pain. GI tract pain is likely caused by accumulation of lipids in the small vasculature of the GI tract which obstructs blood flow and causes pain.

Kidney complications are a common and serious effect of the disease; kidney insufficiency and kidney failure may worsen throughout life. The presence of protein in the urine (which causes foamy urine) is often the first sign of kidney involvement. End-stage kidney failure in those with Fabry disease typically occurs in the third decade of life, and is a common cause of death due to the disease.

Wissler's syndrome (or Wissler's disease or Wissler-Fanconi syndrome) is a rheumatic disease that has a similar presentation to sepsis. It is sometimes considered closely related to Still's disease. It is named for Guido Fanconi and Hans Wissler It was first described by Wissler in 1944 and Fanconi in 1946. Single observations by E. Uhse in 1943 («Febris maculosa intermittens»), Fykow in 1929 and Nowak in 1942.

Four cardinal symptoms have sometimes been used as diagnostic criteria:

1. painful, fatty lipomas (benign fatty tumors) across anatomy

2. obesity, frequently in menopausal age

3. weakness and fatigue

4. emotional instability, depression, epilepsy, confusion, and dementia.

There are also potential signs of the disease which are identified as the following:

However, as it is unclear which symptoms are cardinal and which symptoms are minor signs in Dercum's disease, it is unclear which should be used as diagnostic criteria. Researchers have proposed a 'minimal definition' based on symptoms most often part of Dercum's disease: 1) Generalized overweight or obesity. 2) Chronic pain in the adipose tissue. The associated symptoms in Dercum's disease include obesity, fatty deposits, easy bruisability, sleep disturbances, impaired memory, depression, difficulty concentrating, anxiety, rapid heartbeat, shortness of breath, diabetes, bloating, constipation, fatigue, weakness and joint and muscle aches. Regarding the associated symptoms in Dercum's disease, only case reports have been published. No study involving medical examinations has been performed in a large group of patients.

The disease appears to be progressive in nature. The Fields twins started having problems when they were four years old. By the time they had reached the age of nine, they were having difficulty walking and needed frames to assist them with walking. Their muscles have been gradually deteriorating over time. The disease affects the twins' nerves, causing them to make involuntary muscle movements such as trembling in the hands.

The extent of the disease is still unknown as the two women are only 21. However, the disease has had no apparent effect on their brains or personalities. Doctors do not know if the disease is fatal and, if so, what the life expectancy of one with this disease is. If the cause of the disease is genetic, there is a chance that the twins could pass it on to their future children.

Adiposis dolorosa, also known as Dercum's disease or Anders disease, is a rare condition characterized by generalized obesity and fatty tumors in the adipose tissue. The tumors are normally painful and found in multiples on the extremities. The cause and mechanism of Dercum's disease remains unknown. Possible causes include nervous system dysfunction, mechanical pressure on nerves, adipose tissue dysfunction, and trauma.

Dercum's disease was first described at Jefferson Medical College by neurologist Francis Xavier Dercum in 1892.

Fields' disease is considered to be one of the rarest known diseases in the world, with only two diagnosed cases in history. The frequency of this disease is therefore 1 in approximately 3.75 billion (although since the disease manifested in identical twins, the actual frequency is 1 in approximately 7.5 billion). It is named after Welsh twins Catherine and Kirstie Fields, of Llanelli. Fields' disease is a neuromuscular disease, causing muscular degeneration.

The disease was first noticed when the twins were around the age of four. Doctors have been unable to identify it and have not been able to match it to any known diseases. As a result, the Fields sisters have undergone numerous tests, but no treatment has yet been found. No definitive cause has been determined and doctors have generally concluded that they were born with it.

Symptoms of inflammatory arthritis include stiffness, pain, and swelling of the joints, restricted motions, and reduced physical strength. Other symptoms may include systemic complaints including fatigue.

Schnitzler syndrome is a rare disease characterised by chronic hives (urticaria) and periodic fever, bone pain and joint pain (sometimes with joint inflammation), weight loss, malaise, fatigue, swollen lymph glands and enlarged spleen and liver.

The urticarial rash is non-itching in more than half of cases, which is unusual for hives. It is most prominent on the trunk, arms and legs, sparing the palms, soles, head and neck. Associated angioedema has been reported in a few patients. A review of 94 cases found a mean age at onset of 51 years, and only four patients developed symptoms before the age of 35. The cause and disease mechanism of Schnitzler syndrome remain largely unknown.

Schnitzler syndrome is considered an autoinflammatory and autoimmune disorder. Chronic hives and a monoclonal gammopathy have been proposed as the major criteria, while the others represent minor criteria.