The signs and symptoms of TTP may at first be subtle and nonspecific. Many people experience an influenza-like or diarrheal illness before developing TTP. Neurological symptoms are very common and vary greatly in severity. Frequently reported symptoms include feeling very tired, confusion, and headaches. Seizures and symptoms similar to those of a stroke can also be seen.

As TTP progresses, blood clots form within small blood vessels (microvasculature), and platelets (clotting cells) are consumed. As a result, bruising, and rarely bleeding can occur. The bruising often takes the form of purpura, while the most common site of bleeding, if it occurs, is from the nose or gums. Larger bruises (ecchymoses) may also develop.

The classic presentation of TTP includes a constellation of five medical signs which classically support the clinical diagnosis of TTP, although it is unusual for patients to present with all 5 symptoms. The pentad includes:

- Fever

- Changes in mental status

- Thrombocytopenia

- Reduced kidney function

- Haemolytic anaemia (microangiopathic hemolytic anemia).

High blood pressure (hypertension) may be found on examination.

While there are several possible causes, they generally result in excessive bleeding and a lack of clotting.

Individuals with congenital hypfibringenemia often lack any symptoms are detected by routine lab testing of fibrinogen or when tested for it because close relatives have symptomatic hypofibrinogenmeia. Indeed, studies indicate that, among family members with the identical congenital hypofibrinogenemia mutation, some never exhibit symptoms and those that are symptomatic develop symptoms only as adults.

Individuals with this disorder are usually less symptomatic than patients with other fibrinogen disorders because their fibrinogen levels are generally sufficient to prevent spontaneous bleeding. Those with particularly low blood fibrinogen levels (<0.5 gram/liter) may develop serious bleeding spontaneously and many with the disorder do so following trauma or surgery. Depending on their fibrinogen levels, women with the disorder may also bleed excessively during delivery and the postpartum period; in rare cases, they may have an increased risk of suffering miscarriages. Individuals with the disorder also suffer thrombotic events which may include blockage of large arteries in relatively young patients who have high levels of cardiovascular risk factors. The thrombi which form in these individuals are unstable, tend to embolize, and may therefore lead to thromboembolic events such as pulmonary embolism. Both bleeding and thrombotic events can occur at separate times or even concurrently in the same individual with the disorder.

Coagulopathy may cause uncontrolled internal or external bleeding. Left untreated, uncontrolled bleeding may cause damage to joints, muscles, or internal organs and may be life-threatening. People should seek immediate medical care for serious symptoms, including heavy external bleeding, blood in the urine or stool, double vision, severe head or neck pain, repeated vomiting, difficulty walking, convulsions, or seizures. They should seek prompt medical care if they experience mild but unstoppable external bleeding or joint swelling and stiffness.

In medicine (hematology), bleeding diathesis (h(a)emorrhagic diathesis) is an unusual susceptibility to bleed (hemorrhage) mostly due to hypocoagulability, in turn caused by a coagulopathy (a defect in the system of coagulation). Several types are distinguished, ranging from mild to lethal. Also, bleeding diathesis can be caused by thinning of the skin or impaired wound healing.

Many cases of congenital dysfibrinogenemia are asymptomatic. Since manifestations of the disorder generally occur in early adulthood or middle-age, younger individuals with a gene mutation causing it may not have had time to develop symptoms while previously asymptomatic individuals of advanced age with such a mutation are unlikely to develop symptoms. Bleeding episodes in most cases of this disorder are mild and commonly involve easy bruising and menorrhagia. Less common manifestations of bleeding may be severe or even life-threatening; these include excessive bleeding after tooth extraction, surgery, vaginal birth, and miscarriage. Rarely, these individuals may suffer hemarthrosis or cerebral hemorrhage. In one study of 37 individuals >50 years old afflicted with this disorder, 19% had a history of thrombosis. Thrombotic complications occur in both arteries and veins and include transient ischemic attack, ischemic stroke, myocardial infarction, retinal artery thrombosis, peripheral artery thrombosis, and deep vein thrombosis. In one series of 33 individuals with a history of thrombosis due to congenital dysfibrinogenemia, five developed chronic pulmonary hypertension due to ongoing pulmonary embolism probably stemming form deep vein thrombosis. About 26% of individuals with the disorder suffer both bleeding and thrombosis complications.

In DIC, the underlying cause usually leads to symptoms and signs, and DIC is discovered on laboratory testing. The onset of DIC can be sudden, as in endotoxic shock or amniotic fluid embolism, or it may be insidious and chronic, as in cancer. DIC can lead to multiorgan failure and widespread bleeding.

Coagulopathy (also called a bleeding disorder) is a condition in which the blood’s ability to coagulate (form clots) is impaired. This condition can cause a tendency toward prolonged or excessive bleeding (bleeding diathesis), which may occur spontaneously or following an injury or medical and dental procedures. Of note, coagulopathies are sometimes erroneously referred to as "clotting disorders"; a clotting disorder is a predisposition to clot formation (thrombus), also known as a hypercoagulable state or thrombophilia.

There are various symptoms that are presented and are typically associated to a specific site that they appear at. Hypoprothrombinemia is characterized by a poor blood clotting function of prothrombin. Some symptoms are presented as severe, while others are mild, meaning that blood clotting is slower than normal. Areas that are usually affected are muscles, joints, and the brain, however, these sites are more uncommon.

The most common symptoms include:

1. Easy bruising

2. Oral mucosal bleeding - Bleeding of the membrane mucus lining inside of the mouth.

3. Soft tissue bleeding.

4. Hemarthrosis - Bleeding in joint spaces.

5. Epistaxis - Acute hemorrhages from areas of the nasal cavity, nostrils, or nasopharynx.

6. Women with this deficiency experience menorrhagia: prolonged, abnormal heavy menstrual bleeding. This is typically a symptom of the disorder when severe blood loss occurs.

Other reported symptoms that are related to the condition:

1. Prolonged periods of bleeding due to surgery, injury, or post birth.

2. Melena - Associated with acute gastrointestinal bleeding, dark black, tarry feces.

3. Hematochezia - Lower gastrointestinal bleeding, passage of fresh, bright red blood through the anus secreted in or with stools. If associated with upper gastrointestinal bleeding, suggestive of a more life-threatening issue.

Type I: Severe hemorrhages are indicators of a more severe prothrombin deficiency that account for muscle hematomas, intracranial bleeding, postoperative bleeding, and umbilical cord hemorrhage, which may also occur depending on the severity, respectively.

Type II: Symptoms are usually more capricious, but can include a variety of the symptoms described previously. Less severe cases of the disorder typically do not involve spontaneous bleeding.

Disseminated intravascular coagulation (DIC) is a condition in which blood clots form throughout the body blocking small blood vessels. Symptoms may include chest pain, shortness of breath, leg pain, problems speaking, or problems moving parts of the body. As clotting factors and platelets are used up, bleeding may occur. This may include blood in the urine, blood in the stool, or bleeding into the skin. Complications may include organ failure.

Relatively common causes include sepsis, surgery, major trauma, cancer, and complications of pregnancy. Less common causes include snake bites, frostbite, and burns. There are two main types acute (rapid onset) and chronic (slow onset). Diagnosis is typically based on blood tests. Findings may include low platelets, low fibrinogen, high INR, or high D-dimer.

Treatment is mainly directed towards the underlying condition. Other measures may include giving platelets, cryoprecipitate, or fresh frozen plasma. Evidence to support these treatments, however, is poor. Heparin may be useful in the chronic form. About 1% of people admitted to hospital are affected by the condition. In those with sepsis rates are between 20% and 50%. The risk of death among those affected varies from 20 to 50%.

Thrombotic thrombocytopenic purpura (TTP) is a rare disorder of the blood-coagulation system, causing extensive microscopic clots to form in the small blood vessels throughout the body, resulting in low platelet counts. These small blood clots, called thrombi, can damage many organs including the kidneys, heart, brain, and nervous system. In the era before effective treatment with plasma exchange, the fatality rate was about 90%. With plasma exchange, this has dropped to 10% at six months. Because the disease generally results from antibodies that activate the immune system to inhibit the ADAMTS13 enzyme, agents that suppress the immune system, such as glucocorticoids, rituximab, cyclophosphamide, vincristine, or ciclosporin, may also be used if a relapse or recurrence follows plasma exchange. Platelets are not transfused unless the patient has a life-threatening bleed, since the transfused platelets would also quickly be consumed by thrombi formation, leading to a minimal increase in circulating platelets.

Most cases of TTP arise from autoantibody-mediated inhibition of the enzyme ADAMTS13, a metalloprotease responsible for cleaving large multimers of von Willebrand factor (vWF) into smaller units. The increase in circulating multimers of vWF increases platelet adhesion to areas of endothelial injury, particularly where arterioles and capillaries meet, which in turn results in the formation of small platelet clots called thrombi. As platelets are used up in the formation of thrombi, this then leads to a decrease in the number of overall circulating platelets, which may then cause life-threatening bleeds. The reason why the antibodies form is generally unknown for most patients, though it can be associated with some medications and autoimmune diseases such as HIV and Lupus, as well as pregnancy.

A rarer form of TTP, called Upshaw–Schulman syndrome, or "Inherited TTP," results from an autosomal recessive gene that leads to ADAMTS13 dysfunction from the time of birth, resulting in persisting large vWF multimers, which in turn results in the formation of thrombi (small platelet clots).

Red blood cells passing the microscopic clots are subjected to shear stress, which damages their membranes, leading to rupture of red blood cells within blood vessels, which in turn leads to anaemia and schistocyte formation. The presence of these blood clots in the small blood vessels reduces blood flow to organs resulting in cellular injury and end organ damage. Current therapy is based on support and plasmapheresis to reduce circulating antibodies against ADAMTS13 and replenish blood levels of the enzyme.

Early purpura fulminans lesions look similar to traumatic skin bleeds or purpuric rashes, such as immune thrombocytopenic purpura or thrombotic thrombocytopenic purpura; however, purpura fulminans will rapidly progress to necrosis whereas other purpuric rashes do not. In most cases, differential diagnoses may be distinguished from purpura fulminans by other clinical and laboratory findings.

The initial appearance of purpura fulminans lesions is of well-demarcated erythematous lesions which progress rapidly to develop irregular central areas of blue-black haemorrhagic necrosis. Advancing areas of necrosis are often surrounded by a thin border of erythema that fades into adjacent unaffected skin. Haemorrhage into the necrotic skin causes purpura fulminans lesions to become painful, dark and raised, sometimes with vesicle or blister (bulla) formation.

The distribution of purpura fulminans lesions may be different according to the underlying pathogenesis. Purpura fulminans in severe sepsis typically develops in the distal extremities and progresses proximally or appears as a generalised or diffuse rash affecting the whole body surface. In cases of severe inheritable protein C deficiency, purpura fulminans with disseminated intravascular coagulation manifests within a few hours or days after birth.

Characteristic symptoms vary with severity. In general symptoms are internal or external bleeding episodes, which are called "bleeds". People with more severe haemophilia suffer more severe and more frequent bleeds, while people with mild haemophilia usually suffer more minor symptoms except after surgery or serious trauma. In cases of moderate haemophilia symptoms are variable which manifest along a spectrum between severe and mild forms.

In both haemophilia A and B, there is spontaneous bleeding but a normal bleeding time, normal prothrombin time, normal thrombin time, but prolonged partial thromboplastin time. Internal bleeding is common in people with severe haemophilia and some individuals with moderate haemophilia. The most characteristic type of internal bleed is a joint bleed where blood enters into the joint spaces. This is most common with severe haemophiliacs and can occur spontaneously (without evident trauma). If not treated promptly, joint bleeds can lead to permanent joint damage and disfigurement. Bleeding into soft tissues such as muscles and subcutaneous tissues is less severe but can lead to damage and requires treatment.

Children with mild to moderate haemophilia may not have any signs or symptoms at birth especially if they do not undergo circumcision. Their first symptoms are often frequent and large bruises and haematomas from frequent bumps and falls as they learn to walk. Swelling and bruising from bleeding in the joints, soft tissue, and muscles may also occur. Children with mild haemophilia may not have noticeable symptoms for many years. Often, the first sign in very mild haemophiliacs is heavy bleeding from a dental procedure, an accident, or surgery. Females who are carriers usually have enough clotting factors from their one normal gene to prevent serious bleeding problems, though some may present as mild haemophiliacs.

The most common conditions associated with thrombophilia are deep vein thrombosis (DVT) and pulmonary embolism (PE), which are referred to collectively as venous thromboembolism (VTE). DVT usually occurs in the legs, and is characterized by pain, swelling and redness of the limb. It may lead to long-term swelling and heaviness due to damage to valves in the veins. The clot may also break off and migrate (embolize) to arteries in the lungs. Depending on the size and the location of the clot, this may lead to sudden-onset shortness of breath, chest pain, palpitations and may be complicated by collapse, shock and cardiac arrest.

Venous thrombosis may also occur in more unusual places: in the veins of the brain, liver (portal vein thrombosis and hepatic vein thrombosis), mesenteric vein, kidney (renal vein thrombosis) and the veins of the arms. Whether thrombophilia also increases the risk of arterial thrombosis (which is the underlying cause of heart attacks and strokes) is less well established.

Thrombophilia has been linked to recurrent miscarriage, and possibly various complications of pregnancy such as intrauterine growth restriction, stillbirth, severe pre-eclampsia and abruptio placentae.

Protein C deficiency may cause purpura fulminans, a severe clotting disorder in the newborn that leads to both tissue death and bleeding into the skin and other organs. The condition has also been described in adults. Protein C and protein S deficiency have also been associated with an increased risk of skin necrosis on commencing anticoagulant treatment with warfarin or related drugs.

Characteristically, there is increased mucosal bleeding:

- menorrhagia

- easy bruising

- epistaxis

- gingival bleeding

- gastrointestinal bleeding

- postpartum bleeding

- increased bleeding post-operatively.

The bleeding tendency is variable but may be severe. Hemarthrosis, particularly spontaneous, is very rare, in contrast to the hemophilias.

Platelet numbers and morphology are normal. Platelet aggregation is normal with ristocetin, but impaired with other agonists such as ADP, thrombin, collagen or epinephrine.

Purpura fulminans is an acute, often fatal, thrombotic disorder which manifests as blood spots, bruising and discolouration of the skin resulting from coagulation in small blood vessels within the skin and rapidly leads to skin necrosis and disseminated intravascular coagulation.

Symptoms usually present from the period of birth to early childhood as: nose bleeds, bruising, and/or gum bleeding. Problems later in life may arise from anything that can cause internal bleeding such as: stomach ulcers, surgery, trauma, or menstruation. Abnormality of the abdomen, Epistaxis, Menorrhagia, Purpura, Thrombocytopenia, and prolonged bleeding time have also been listed as symptoms of various Giant Platelet Disorders.

The dysfibrinogenemias consist of three types of fibrinogen disorders in which a critical blood clotting factor, fibrinogen, circulates at normal levels but is dysfunctional. Congenital dysfibrinogenemia is an inherited disorder in which one of the parental genes produces an abnormal fibrinogen. This fibrinogen interferes with normal blood clotting and/or lyses of blood clots. The condition therefore may cause pathological bleeding and/or thrombosis. Acquired dysfibrinogenemia is a non-hereditary disorder in which fibrinogen is dysfunctional due to the presence of liver disease, autoimmune disease, a plasma cell dyscrasias, or certain cancers. It is associated primarily with pathological bleeding. Hereditary fibrinogen Aα-Chain amyloidosis is a sub-category of congenital dysfibrinogenemia in which the dysfunctional fibrinogen does not cause bleeding or thrombosis but rather gradually accumulates in, and disrupts the function of, the kidney.

Congenital dysfibrinogenmia is the commonest of these three disorders. Some 100 different genetic mutations occurring in more than 400 families have been found to cause it. All of these mutations as well as those causing hereditary fibrinogen Aα-Chain amyloidosis exhibit partial penetrance, i.e. only some family members with one of these mutant genes develop dysfibrinogenemia-related symptoms. While both of these congenital disorders as well as acquired dysfibrinogenemia are considered very rare, it is estimated that ~0.8% of individuals with venous thrombosis have either a congenital or acquired dysfibrinogenemia. Hence, the dysfibrinogenemia disorders may be highly under-diagnosed conditions due to isolated thrombotic events that are not appreciated as reflecting an underlying fibrinogen disorder.

Congenital dysfibrinogenemia is distinguished from a similar inherited disorder, congenital hypodysfibrinogenemia. Both disorders involve the circulation of dysfunctional fibrinogen but in congenital hypodysfibrinogenemia plasma fibrinogen levels are low while in congenital dysfibrinogenemia they are normal. Furthermore, the two disorders involve different gene mutations and inheritance patterns as well as somewhat different symptoms.

In terms of the symptoms of Hemophilia A there are internal or external bleeding episodes. Individuals with more severe haemophilia suffer more severe and more frequent bleeding, while others with mild haemophilia typically suffer more minor symptoms except after surgery or serious trauma. Moderate haemophiliacs have variable symptoms which manifest along a spectrum between severe and mild forms.

Prolonged bleeding from a venepuncture or heelprick is another common early sign of haemophilia, these signs may lead to blood tests which indicates haemophilia. In other people, especially those with moderate or mild haemophilia any trauma will lead to the first serious "bleed". Haemophilia leads to a severely increased risk of prolonged bleeding from common injuries, or in severe cases bleeding may be spontaneous and without obvious cause. Bleeding may occur anywhere in the body, superficial bleeding such as those caused by abrasions, or shallow lacerations may be prolonged and the scab may easily be broken up due to the lack of fibrin, which may cause re-bleeding. While superficial bleeding is troublesome, some of the more serious sites of bleeding are:

- Joints

- Muscles

- Digestive tract

- Brain

Muscle and joint haemorrhages - or haemarthrosis - are indicative of haemophilia, while digestive tract and cerebral haemorrhages are also germane to other coagulation disorders.Though typically not life-threatening, joint bleeding is one of the most serious symptoms of haemophilia. Repeated bleeds into a joint capsule can cause permanent joint damage and disfigurement resulting in chronic arthritis and disability. Joint damage is not a result of blood in the capsule but rather the healing process. When blood in the joint is broken down by enzymes in the body, the bone in that area is also degraded, this exerts a lot of pain upon the person afflicted with the disease.

Thrombophilia (sometimes hypercoagulability or a prothrombotic state) is an abnormality of blood coagulation that increases the risk of thrombosis (blood clots in blood vessels). Such abnormalities can be identified in 50% of people who have an episode of thrombosis (such as deep vein thrombosis in the leg) that was not provoked by other causes. A significant proportion of the population has a detectable abnormality, but most of these only develop thrombosis in the presence of an additional risk factor.

There is no specific treatment for most thrombophilias, but recurrent episodes of thrombosis may be an indication for long-term preventative anticoagulation. The first major form of thrombophilia, antithrombin deficiency, was identified in 1965, while the most common abnormalities (including factor V Leiden) were described in the 1990s.

Bernard–Soulier syndrome often presents as a bleeding disorder with symptoms of:

Symptoms may differ greatly, as apparently modifiers control to some degree the amount of FVII that is produced. Some affected individuals have few or no symptoms while others may experience life-threatening bleeding. Typically this bleeding disorder manifests itself as a tendency to easy bruising, nose bleeding, heavy and prolonged menstruation, and excessive bleeding after dental or surgical interventions. Newborns may bleed in the head, from the umbilicus, or excessively after circumcision. Other bleeding can be encountered in the gut, in muscles or joints, or the brain. Hematuria may occur.

While in congenital disease symptoms may be present at birth or show up later, in patients with acquired FVII deficiency symptoms typically show up in later life.

About 3-4% of patients with FVII deficiency may also experience thrombotic episodes.

Warfarin-induced skin necrosis (or, more generally, Anticoagulant-induced skin necrosis) is a condition in which skin and subcutaneous tissue necrosis (tissue death) occurs due to acquired protein C deficiency following treatment with anti-vitamin K anticoagulants (4-hydroxycoumarins, such as warfarin).

Warfarin necrosis is a rare but severe complication of treatment with warfarin or related anticoagulants. The typical patient appears to be an obese, middle aged woman (median age 54 years, male to female ratio 1:3). This drug eruption usually occurs between the third and tenth days of therapy with warfarin derivatives. The first symptoms are pain and redness in the affected area. As they progress, lesions develop a sharp border and become petechial, then hard and purpuric. They may then resolve or progress to form large, irregular, bloody bullae with eventual necrosis and slow-healing eschar formation. Favored sites are breasts, thighs, buttocks and penis, all areas with subcutaneous fat. In rare cases, the fascia and muscle are involved.

Development of the syndrome is associated with the use of large loading doses at the start of treatment.

Severe complications are much more common in cases of severe and moderate haemophilia. Complications may arise from the disease itself or from its treatment:

- Deep internal bleeding, e.g. deep-muscle bleeding, leading to swelling, numbness or pain of a limb.

- Joint damage from haemarthrosis (haemophilic arthropathy), potentially with severe pain, disfigurement, and even destruction of the joint and development of debilitating arthritis.

- Transfusion transmitted infection from blood transfusions that are given as treatment.

- Adverse reactions to clotting factor treatment, including the development of an immune inhibitor which renders factor replacement less effective.

- Intracranial haemorrhage is a serious medical emergency caused by the buildup of pressure inside the skull. It can cause disorientation, nausea, loss of consciousness, brain damage, and death.

Haemophilic arthropathy is characterized by chronic proliferative synovitis and cartilage destruction. If an intra-articular bleed is not drained early, it may cause apoptosis of chondrocytes and affect the synthesis of proteoglycans. The hypertrophied and fragile synovial lining while attempting to eliminate excessive blood may be more likely to easily rebleed, leading to a vicious cycle of hemarthrosis-synovitis-hemarthrosis. In addition, iron deposition in the synovium may induce an inflammatory response activating the immune system and stimulating angiogenesis, resulting in cartilage and bone destruction.