Understanding the Medical Term Purpur
The word "purpur" is not a complete medical term in itself, but rather a combining form or root, purpur-, derived from the Latin word for purple. It is most famously used in the term purpura, which refers to the visible symptom of bleeding under the skin. This causes purple-red patches or spots that do not lose their color when pressure is applied, unlike other types of rashes. The size and appearance of these spots can vary, leading to further classifications like petechiae and ecchymoses.
What Causes Purpura?
Purpura is a symptom, not a disease, and its underlying causes are diverse, often stemming from issues with blood platelets, blood vessels, or clotting factors. A doctor must investigate the root cause to determine the appropriate course of action.
Types of Purpura Explained
Medical professionals classify purpura into two main categories based on a patient's platelet count.
Thrombocytopenic Purpura
This type occurs when there is a lower-than-normal platelet count in the blood. Platelets are crucial for blood clotting, so a deficiency can lead to excessive bleeding. Causes include:
- Immune Thrombocytopenia (ITP): An autoimmune disorder where the body attacks its own platelets.
- Medications: Certain drugs can reduce the platelet count as a side effect.
- Infections: Severe infections, like HIV, Hepatitis C, or bacterial bloodstream infections (meningococcemia), can trigger a low platelet count.
- Diseases: Conditions that impair bone marrow function, such as leukemia or aplastic anemia, can hinder platelet production.
Non-Thrombocytopenic Purpura
This form occurs when a person has a normal platelet count, but the blood vessels are damaged or fragile, leading to leakage. Common causes include:
- Henoch-Schönlein Purpura (HSP): An inflammation of small blood vessels often triggered by a respiratory infection, particularly in children.
- Senile (Actinic) Purpura: A benign condition in older adults where skin and blood vessels become more fragile with age and sun exposure, leading to bruising from minor trauma.
- Scurvy: A severe lack of vitamin C, which is essential for collagen synthesis and maintaining healthy blood vessel walls.
- Vasculitis: A general term for inflammation of the blood vessels.
How Do Doctors Diagnose Purpura?
Diagnosing purpura involves identifying the underlying cause. A medical professional will likely perform a physical examination and take a detailed medical history. Diagnostic steps may include:
- Visual Inspection: Checking the size, location, and nature of the spots.
- Blood Tests: A complete blood count (CBC) is standard to measure platelet levels. Additional tests can look for signs of infection, inflammation, or autoimmune conditions.
- Urine Tests: These are particularly important if Henoch-Schönlein purpura is suspected, as it can affect the kidneys.
- Skin Biopsy: A small tissue sample may be taken to confirm the diagnosis and rule out other conditions, including some types of skin cancer.
- Bone Marrow Testing: In rare cases, if a bone marrow disorder is suspected, a biopsy might be performed.
The Difference Between Purpura, Petechiae, and Ecchymoses
These terms all describe bleeding under the skin, but they are distinguished by size. It is a common point of confusion that this table helps to clarify.
| Feature | Petechiae | Purpura | Ecchymosis |
|---|---|---|---|
| Appearance | Pinpoint, red-purple spots | Larger red or purple patches | A large, bruised area |
| Size | Less than 2 mm in diameter | 2 mm to 1 cm in diameter | Greater than 1 cm in diameter |
| Cause | Leaking capillaries, can be part of purpura | Leaking small blood vessels | Leaking larger blood vessels or a cluster of purpura |
| Example | Often seen in clusters on the lower legs or abdomen | Characteristic rash of Henoch-Schönlein purpura | A common bruise from an injury |
Treatment Options for Purpura
Treatment for purpura focuses on addressing the root cause, as it is a symptom rather than a standalone disease. In many mild cases, such as senile purpura or simple viral-induced purpura in children, no treatment is needed, and the condition resolves on its own.
- Medication: For autoimmune or inflammatory causes, corticosteroids or other immune-suppressing drugs may be used. In severe cases of thrombocytopenia, medications like romiplostim or eltrombopag may stimulate platelet production.
- Underlying Disease Management: If purpura is caused by an infection, cancer, or other systemic disease, treating that condition is the primary goal.
- Supportive Care: For conditions like Henoch-Schönlein purpura, managing symptoms with rest and pain medication is common.
Conclusion
While the medical term "purpur" technically refers to the combining form for the color purple, it is the condition of purpura that is of clinical importance. This visible sign of bleeding under the skin can have a wide range of causes, from minor and benign issues to more serious underlying health problems affecting platelets, blood vessels, or clotting function. A thorough medical evaluation is essential to determine the specific type and cause of purpura, leading to the correct diagnosis and management plan.
For more in-depth information on immune thrombocytopenia (ITP), a common cause of purpura, consult the resources from the National Institutes of Health. NIH: Immune Thrombocytopenia.
