Waldenström hyperglobulinemic purpura (also known as "Purpura hyperglobulinemica") is a skin condition that presents with episodic showers of petechiae (small red or purple spots) occurring on all parts of the body, most profusely on the lower extremities.

Nonthrombocytopenic purpura is a type of purpura (red or purple skin discoloration) not associated with thrombocytopenia.

Examples/causes include:

- Henoch–Schönlein purpura.

- Hereditary hemorrhagic telangiectasia

- Congenital cytomegalovirus

- Meningococcemia

Purpura is a condition of red or purple discolored spots on the skin that do not blanch on applying pressure. The spots are caused by bleeding underneath the skin usually secondary to vasculitis or dietary deficiency of vitamin C (scurvy). They measure 0.3–1 cm (3–10 mm), whereas petechiae measure less than 3 mm, and ecchymoses greater than 1 cm.

Purpura is common with typhus and can be present with meningitis caused by meningococci or septicaemia. In particular, meningococcus ("Neisseria meningitidis"), a Gram-negative diplococcus organism, releases endotoxin when it lyses. Endotoxin activates the Hageman factor (clotting factor XII), which causes disseminated intravascular coagulation (DIC). The DIC is what appears as a rash on the affected individual.

Purpura are a common and nonspecific medical sign; however, the underlying mechanism commonly involves one of:

- Platelet disorders (thrombocytopenic purpura)

- Primary thrombocytopenic purpura

- Secondary thrombocytopenic purpura

- Post-transfusion purpura

- Vascular disorders (nonthrombocytopenic purpura)

- Microvascular injury, as seen in senile (old age) purpura, when blood vessels are more easily damaged

- Hypertensive states

- Deficient vascular support

- Vasculitis, as in the case of Henoch–Schönlein purpura

- Coagulation disorders

- Disseminated intravascular coagulation (DIC)

- Scurvy (vitamin C deficiency) - defect in collagen synthesis due to lack of hydroxylation of procollagen results in weakened capillary walls and cells

- Meningococcemia

- Cocaine use with concomitant use of the one-time chemotherapy drug and now veterinary deworming agent levamisole can cause purpura of the ears, face, trunk, or extremities, sometimes needing reconstructive surgery. Levamisole is purportedly a common cutting agent.

- Decomposition of blood vessels including purpura is a symptom of acute radiation poisoning in excess of 2 Grays of radiation exposure. This is an uncommon cause in general, but is commonly seen in victims of nuclear disaster.

Cases of psychogenic purpura are also described in the medical literature, some claimed to be due to "autoerythrocyte sensitization". Other studies suggest the local (cutaneous) activity of tissue plasminogen activator can be increased in psychogenic purpura, leading to substantial amounts of localized plasmin activity, rapid degradation of fibrin clots, and resultant bleeding. Petechial rash is also characteristic of a rickettsial infection.

Drug-induced purpura is a skin condition that may be related to platelet destruction, vessel fragility, interference with platelet function, or vasculitis.

Cryoglobulinemic purpura is a skin condition characterized by purpura and occurring most frequently in multiple myeloma and macroglobulinemia.

Doucas and Kapetanakis pigmented purpura is a skin condition characterized by scaly and eczematous patches, which also have petechiae and hemosiderin staining.

It is also known as "eczematoid purpura" or "eczematoid-like purpura".

It was characterized in 1953.

Amyloid purpura affects a minority of individuals with amyloidosis. For example, purpura is present early in the disease in approximately 15% of patients with primary systemic amyloidosis.

Treat the underlying disease . Eg for wegner's treatment is steroids and cyclophosphamide.

Cryofibrinogenemic purpura is a skin condition that manifests as painful purpura with slow healing ulcerations and edema of both feet during winter months.

Overall prognosis is good in most patients, with one study showing recovery occurring in 94% and 89% of children and adults, respectively (some having needed treatment). In children under ten, the condition recurs in about a third of all cases and usually within the first four months after the initial attack. Recurrence is more common in older children and adults.

Solar purpura (also known as "Actinic purpura," and "Senile purpura") is a skin condition characterized by large, sharply outlined, 1- to 5-cm, dark purplish-red ecchymoses appearing on the dorsa of the forearms and less often the hands.

The condition is most common in elderly people of European descent. It is caused by sun-induced damage to the connective tissue of the skin.

No treatment is necessary. The lesions typically fade over a period of up to 3 weeks.

HSP occurs more often in children than in adults, and usually follows an upper respiratory tract infection. Half of affected patients are below the age of six, and 90% are under ten. It occurs about twice as often in boys as in girls. The incidence of HSP in children is about 20 per 100,000 children per year, making it the most common vasculitis in children.

Cases of HSP may occur anytime throughout the year, but some studies have found that fewer cases occur during the summer months.

Thrombocytopenic purpura are purpura associated with a reduction in circulating blood platelets which can result from a variety of causes, such as kaposi sarcoma.

By tradition, the term idiopathic thrombocytopenic purpura is used when the cause is idiopathic. However, most cases are now considered to be immune-mediated.

Another form is thrombotic thrombocytopenic purpura.

Purpura fulminans is rare and most commonly occurs in babies and small children but can also be a rare manifestation in adults when it is associated with severe infections. For example, Meningococcal septicaemia is complicated by purpura fulminans in 10–20% of cases among children. Purpura fulminans associated with congenital (inherited) protein C deficiency occurs in 1:500,000–1,000,000 live births.

The precise cause of amyloid purpura is unknown, but several mechanisms are thought to contribute. One may be a decrease in the level of circulating factor X, a clotting factor necessary for coagulation. The proposed mechanism for this decrease in factor X is that circulating amyloid fibrils bind and inactivate factor X. Another contributing factor may be enhanced fibrinolysis, the breakdown of clots. Subendothelial deposits of amyloid may weaken blood vessels and lead to the extravasation of blood. Amyloid deposits in the gastrointestinal tract and liver may also play a role in the development of amyloid purpura.

Rheumatoid vasculitis is skin condition that is a typical feature of rheumatoid arthritis, presenting as peripheral vascular lesions that are localized purpura, cutaneous ulceration, and gangrene of the distal parts of the extremities.

Schamberg's disease is caused by leaky blood vessels near the surface of the skin, capillaries, which allow red blood cells to slip through into the skin. The red blood cells in the skin then fall apart and release their iron, which is released from hemoglobin. The iron causes a rust color and this accounts for the orange tint of the rash that can be seen on the skin. The underlying cause of the leaky blood vessels is not known, but researchers are suggesting that there could be some potential triggers. Some possible triggers include viral infection, a hypersensitivity to some agent, and interaction of some medications, such as thiamine and aspirin. Even though there is no correlation with genetics, there have been a few cases where few people in a family had this condition.

Although the cause of capillary inflammation is unknown, certain preventive measures can be taken. Doctors may prescribe medications that enhance the circulation of blood, which can keep blood vessels strong and healthy. Daily intake of vitamin C has proven to be a natural home remedy that can prevent the onsite of any disease or infection. Doctors always recommend that their patients monitor what they eat because their diet could be a possible factor that contributes to this condition. A healthy body that receives nutritious meals is more likely to have a healthy life that does not revolve around a lot of health problems.

Cutaneous small-vessel vasculitis, also known as hypersensitivity vasculitis, cutaneous leukocytoclastic vasculitis, hypersensitivity angiitis, cutaneous leukocytoclastic angiitis, cutaneous necrotizing vasculitis and cutaneous necrotizing venulitis, is inflammation of small blood vessels (usually post-capillary venules in the dermis), characterized by palpable purpura. It is the most common vasculitis seen in clinical practice.

"Leukocytoclastic" refers to the damage caused by nuclear debris from infiltrating neutrophils in and around the vessels.

Cutaneous vasculitis can have various causes including but not limited to medications, bacterial and viral infections or allergens. It is estimated that 45-55% of cases are idiopathic, meaning the cause is unknown. In cases where a cause can be determined, medications and infectious pathogens are most common in adults, while IgA vasculitis (Henoch-Schönlein purpura) frequently affects children. Other etiologies include autoimmune conditions and malignancies, usually hematologic (related to the blood).

The small vessels in the skin affected are located in the superficial dermis and include arterioles (small arteries carrying blood to capillaries), capillaries, and venules (small veins receiving blood from capillaries). In general, immune complexes deposit in vessel walls leading to activation of the complement system. C3a and C5a, proteins produced from the complement system, attract neutrophils to the vessels. Once activated, neutrophils then release preformed substances, including enzymes causing damage to vessel tissue. Evidence of this process can be seen with a sample of removed skin tissue, or biopsy, viewed under a microscope. Neutrophils are seen surrounding blood vessels and their debris within vessel walls, causing fibrinoid necrosis. This finding on histological examination is termed “leukocytoclastic vasculitis”.

Considering the wide range of potential causes leading to cutaneous small vessel vasculitis, there are subtle variations in the underlying pathophysiology for each cause. For example, medications are metabolized to smaller molecules that can attach to proteins in the blood or vessel walls. The immune system senses these altered proteins as foreign and produces antibodies in efforts to eliminate them from the body. A similar process occurs with infectious agents, such as bacteria, in which antibodies target microbial components.

Hemosiderin hyperpigmentation is pigmentation due to deposits of hemosiderin, and occurs in purpura, hemochromotosis, hemorrhagic diseases, and stasis dermatitis.

Palpable purpura is a condition where purpura, which constitutes visible non-blanching hemorrhages, are raised and able to be touched or felt upon palpation. It indicates some sort of vasculitis secondary to a serious disease.

Microvascular occlusion refers to conditions that can present with retiform purpura.

It has been suggested that phenylephrine may be a cause.

Vasculitis secondary to connective tissue disorders. Usually secondary to systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), relapsing polychondritis, Behçet's disease, and other connective tissue disorders.

Vasculitis secondary to viral infection. Usually due to hepatitis B and C, HIV, cytomegalovirus, Epstein-Barr virus, and Parvo B19 virus.