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 secondary to platelet disorders, vascular disorders, coagulation disorders, or other causes. They measure 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. Classification
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
Clumping fibrillary protein deposits caused by Amyloidosis
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.
Others use the general category label of PDD because they are hesitant to diagnose very young children with a specific type of PDD, such as autism. Both approaches contribute to confusion about the term, because the term PDD actually refers to a category of disorders and is not a diagnostic label. Signs and symptoms
Symptoms of PDD may include behavioral and communication problems such as:

Difficulty using and understanding language
Difficulty relating to people, objects, and events; for example, lack of eye contact, pointing behavior, and lack of facial responses
Unusual play with toys and other objects. Paranoia, a characteristic form of social anxiety, derealization, transient psychosis, and unconventional beliefs if environment or routine are changed without notice
Repetitive body movements or behavior patterns, such as hand flapping, hair twirling, foot tapping, or more complex movements
Difficulty regulating behaviors and emotions, which may result in temper tantrums, anxiety, and aggression
Emotional breakdowns
Delusional or unconventional perception of the world
Maladaptive daydreaming
Mirrored-Self Misidentification – the delusion that the individual in the mirror that you are, is a child, even though you are an older teen or an adult

Degrees
Children with PDD vary widely in abilities, intelligence, and behaviors. Some children do not speak at all, others speak in limited phrases or conversations, and some have relatively normal language development. Repetitive play skills and limited social skills are generally evident. Unusual responses to sensory information – loud noises, lights – are common. Diagnosis
Diagnosis is usually made during early childhood.