The histiocytosis of Rosai–Dorfman disease can occur in lymph nodes, causing lymphadenopathy, or can occur outside lymph nodes in extranodal disease.

Lymphadenopathy can occur in one or more groups of lymph nodes. Among 358 cases of Rosai–Dorfman disease that Rosai collected in a disease registry for which the location of lymphadenopathy was specified, 87.3% had cervical lymphadenopathy. Axillary, inguinal, and mediastinal lymphadenopathy are also found in Rosai–Dorfman disease.

Lymphadenopathy of the axillary lymph nodes can be defined as solid nodes measuring more than 15 mm without fatty hilum. Axillary lymph nodes may be normal up to 30 mm if consisting largely of fat.

Lymphadenopathy or adenopathy is disease of the lymph nodes, in which they are abnormal in size, number, or consistency. Lymphadenopathy of an inflammatory type (the most common type) is lymphadenitis, producing swollen or enlarged lymph nodes. In clinical practice, the distinction between lymphadenopathy and lymphadenitis is rarely made and the words are usually treated as synonymous. Inflammation of the lymphatic vessels is known as lymphangitis. Infectious lymphadenitides affecting lymph nodes in the neck are often called scrofula.

The term comes from the word lymph and a combination of the Greek words , "adenas" ("gland") and , "patheia" ("act of suffering" or "disease").

Lymphadenopathy is a common and nonspecific sign. Common causes include infections (from minor ones such as the common cold to dangerous ones such as HIV/AIDS), autoimmune diseases, and cancers. Lymphadenopathy is also frequently idiopathic and self-limiting.

Vulvar Paget disease presents as a variety of clinical lesions that may occur over a protracted course. Initially it is velvety, soft, and red or bright pink with scattered white islands of hyperkeratosis. (a strawberry and cream appearance) The lesions become erythematous, plaque like, and desquamating especially when located in dry areas. Rarely the appearance is ulcerated. The borders appear irregular, slightly elevated, and sharply demarcated. The visible borders of vulvar Paget disease are often misleading as Paget cells may spread along the basal layers of normal appearing skin with multicentric foci. Involvement may be extensive including the perianal region, genitocrural, and inguinal folds. Clinical examination should determine the presence of periurethral and perianal lesions. In these cases an involvement of the skin by a noncutaneous internal neoplasm may occur.

Symptoms are not specific; most patients report itching, burning, and soreness. A small subset of patients may be asymptomatic. Presence of vulvar pain, bleeding, and tumor formation are reported to be more common in patients affected by invasive disease.Signs and symptoms are skin lesions, often mistaken as eczema, that may be itchy or painful.

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.

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.

Kyrle disease symptoms are chronic and have an onset during adulthood between the ages of 30 and 50 years of age. However, there were reported cases of early onset as early as 5 years of age and late onset as late as 75 years of age. The main symptom is the development of small papules into painless lesions that are surrounded by silvery scales. The lesions are painless, however, there is a chance that the patient may experience extreme urges to itch them. In time, these lesions grow up to a radius of 0.75 inch and develop into red-brown nodules with a central plug of keratin. As more lesions develop, they can come together and form larger keratotic plaques. These lesions are usually observed on the lower extremities, however, can also develop on the upper extremities, such as, the arms, the head and the neck. The only parts of the body that Kyrle disease do not form are the palms, soles, and mucous membranes. Lesions may heal spontaneously without treatment, however, new ones will develop in its place.

Other symptoms that may be observed:

- Hyperkeratotic cone-shaped papular plugs

- Hyperkeratotic verrucous plaques

- Diabetes mellitus

- Hepatic insufficiency

- Presence of albumin in the urine

- Excess sugar in the urine

Kyrle disease or hyperkeratosis follicularis et parafollicularis in cutem penetrans is identified as a form of an acquired perforating disease. Other major perforating diseases are elastosis perforans serpiginosa and reactive perforating collagenosis. Recently, however, there is a controversy on categorizing Kyrle disease with perforating dermatosis or a subtype of acquired perforating collagenosis.

Kyrle disease was first described by Josef Kyrle in 1916 when a diabetic woman presented generalized hyperkeratotic nodules. The disease is distinguished by large papules with central keratin plus on the skin, usually on the legs of the patient and is often in conjunction with hepatic, renal or diabetic disorders. It can affect both females and males with a 6:1 ratio. The papules usually show up on the patient with an average age of 30 years. Kyrle disease is a rare disease unless there is a high count of patients with chronic renal failure. The disease seems to be more prevalent in African Americans, which can be correlated to the high incidence of diabetes mellitus and renal failure in the population.

The most common presentation of Milroy Disease is bilateral lower extremity lymphedema, and may also be accompanied by hydrocele.

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.

CNS involvement most often occurs as a chronic meningoencephalitis. Lesions tend to occur in the brainstem, the basal ganglia and deep hemispheric white matter and may resemble those of MS. Brainstem atrophy is seen in chronic cases.

Neurological involvements range from aseptic meningitis to vascular thrombosis such as dural sinus thrombosis and organic brain syndrome manifesting with confusion, seizures, and memory loss. Sudden hearing loss (Sensorineural) is often associated with it. They often appear late in the progression of the disease but are associated with a poor prognosis.

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.

Although the dermatological changes are the most obvious symptoms of Urbach–Wiethe disease, many patients also have neurological symptoms. About 50–75% of the diagnosed cases of Urbach–Wiethe disease also show bilateral symmetrical calcifications on the medial temporal lobes. These calcifications often affect the amygdala and the periamygdaloid gyri. The amygdala is thought to be involved in processing biologically relevant stimuli and in emotional long term memory, particularly those associated with fear, and both PET and MRI scans have shown a correlation between amygdala activation and episodic memory for strongly emotional stimuli. Therefore, Urbach–Wiethe disease patients with calcifications and lesions in these regions may suffer impairments in these systems. These calcifications are the result of a buildup of calcium deposits in the blood vessels within this brain region. Over time, these vessels harden and the tissue they are a part of dies, causing lesions. The amount of calcification is often related to disease duration. The true prevalence of these calcifications is difficult to accurately state as not all patients undergo brain imaging. Some patients also exhibit epilepsy and neuropsychiatric abnormalities. Epilepsy symptoms could begin with light anxiety attacks and it can be controlled with "Epilum" (Epilepsy Medicine) Other patients present with symptoms similar to schizophrenia while some suffer from mood, anxiety, and psychotic disorders.

Disease onset is typically in early infancy but may occur later in life. Children who have the classic form of Farber disease develop symptoms within the first few weeks of life. These symptoms may include moderately impaired mental ability and problems with swallowing. The liver, heart and kidneys may also be affected. Other symptoms may include vomiting, arthritis, swollen lymph nodes, swollen joints, joint contractures (chronic shortening of muscles or tendons around joints), hoarseness and xanthomas which thicken around joints as the disease progresses. Patients with breathing difficulty may require a breathing tube.

Milroy's disease (MD) is a familial disease characterized by lymphedema, commonly in the legs, caused by congenital abnormalities in the lymphatic system. Disruption of the normal drainage of lymph leads to fluid accumulation and hypertrophy of soft tissues. It is also known as Milroy disease, Nonne-Milroy-Meige syndrome and hereditary lymphedema.

It was named by Sir William Osler for William Milroy, a Canadian physician, who described a case in 1892, though it was first described by Rudolf Virchow in 1863.

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.

Although symptoms can vary greatly between affected individuals, even those within the same family, symptoms normally begin in infancy and are typically a result of thickening skin and mucous membranes. The first symptom is often a weak cry or a hoarse voice due to a thickening of the vocal cords. The hoarse voice can be one of the most striking clinical manifestations of the disease. Lesions and scars also appear on the skin, usually the face and the distal parts of the limbs. This is often the result of poor wound healing and the scarring continues to increase as the patient ages, leaving the skin with a waxy appearance. Skin may be easily damaged as a result of only a minor trauma or injury, leaving many blisters and additional scars. The skin is also usually very dry and wrinkly. White or yellow infiltrates form on the lips, buccal mucosa, tonsils, uvula, epiglottis and frenulum of the tongue. This can lead to upper respiratory tract infection and sometimes requires tracheostomy to relieve the symptom. Too much thickening of the frenulum can restrict tongue movement and may result in speech impediments. Beading of the papules around the eyelids is a very common symptom and is often used as part of a diagnosis of the disease. Some other dermatological symptoms that are sometimes seen but less common include hair loss, parotitis and other dental abnormalities, corneal ulceration, and focal degeneration of the macula.

The Xanthogranulomatous Process (XP), also known as Xanthogranulomatous Inflammation is a form of acute and chronic inflammation characterized by an exuberant clustering of foamy macrophages among other inflammatory cells. Localization in the kidney and renal pelvis has been the most frequent and better known occurrence followed by that in the gallbladder but many others have been subsequently recorded. The pathological findings of the process and etiopathogenetic and clinical observations have been reviewed by Cozzutto and Carbone.

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.

Grover's disease often starts quite suddenly. There are intensely itchy spots on the central back, mid chest and occasionally elsewhere. Frequently, it follows sweating or some unexpected heat stress.

The itchy eruption lasts an average of 10–12 months. It is characterized by papules and papulovesicles with excoriations occurring on the chest, back, lower sternum, arms, and thighs. The papules are most commonly found on the mid chest.

Sometimes the features of Grover's are found in people who do not itch or have a conspicuous rash. Most of the people with Grover's who visit a dermatologist, however, itch a lot.

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.

Farber disease (also known as Farber's lipogranulomatosis, ceramidase deficiency, "Fibrocytic dysmucopolysaccharidosis," and "Lipogranulomatosis") is an extremely rare (80 cases reported worldwide to this day) autosomal recessive lysosomal storage disease marked by a deficiency in the enzyme ceramidase that causes an accumulation of fatty material sphingolipids leading to abnormalities in the joints, liver, throat, tissues and central nervous system. Normally, the enzyme ceramidase breaks down fatty material in the body’s cells. In Farber Disease, the gene responsible for making this enzyme is mutated. Hence, the fatty material is never broken down and, instead, accumulates in various parts of the body, leading to the signs and symptoms of this disorder.

Grover's disease (GD) is a polymorphic, pruritic, papulovesicular dermatosis characterized histologically by acantholysis with or without dyskeratosis. Once confirmed, most cases of Grover's disease last six to twelve months, which is why it was originally called "transient". However it may last much longer. Nevertheless, it is not to be confused with relapsing linear acantholytic dermatosis.