Moderate Higher Hematocrit (Hct) than Normal

Hematocrit is the percentage of your blood that is made up of red blood cells (RBCs). Imagine your blood as a mix of liquid (plasma), white cells, platelets, and red cells. The hematocrit tells you how much of that mix is red cells. A normal hematocrit level is roughly 38–48% for women and 42–52% for men, but the exact numbers can vary slightly depending on the lab and your age. When the hematocrit level rises higher than normal, it means the blood is becoming thicker or more concentrated with red blood cells.

Hematocrit (Hct) measures the percentage of red blood cells (RBCs) in total blood volume. A “moderate high hematocrit” refers to Hct values just above the upper normal limit—typically 52–60% in men and 48–60% in women. Unlike mild elevations (52–55% in men, 48–51% in women) or severe elevations (>60%), moderate high Hct can still strain the heart and blood vessels. Chronically elevated Hct increases blood viscosity, slowing flow and raising the risk of clots, headaches, dizziness, and fatigue. Understanding and lowering moderate high Hct is vital to reduce complications such as stroke or deep vein thrombosis.

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What Does “Moderate Higher Hct” Mean?

A “moderate” increase in hematocrit means your levels are above normal but not in the extreme range where the blood is dangerously thick. For example, if a man’s hematocrit is around 54% (slightly above the upper normal limit), it’s considered moderately high. At this stage, the blood can still flow, but it’s thicker and can strain the heart, lungs, and circulation over time. It is a warning sign that something in the body may be increasing red cell production or reducing blood plasma.

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Why Does Hematocrit Go Up?

Red blood cells carry oxygen throughout the body. The body may increase red blood cells (and hematocrit) when it senses low oxygen levels, dehydration, or certain medical problems. Moderate high hematocrit isn’t always dangerous, but it’s often a signal that your body is trying to adapt to something—like living at high altitude or being dehydrated—or there’s an underlying condition that needs attention.

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Types of Higher Hematocrit

1. Relative Hematocrit Increase – This happens when plasma (the fluid in your blood) goes down, like when you’re dehydrated. The red blood cell count stays the same, but the blood looks more concentrated.

2. Absolute Hematocrit Increase – This means the body is actually producing more red blood cells, often due to bone marrow activity or chronic low oxygen.

3. Primary Polycythemia – This is when the bone marrow makes too many red blood cells without a clear need, such as in polycythemia vera, which is a rare blood disorder.

4. Secondary Polycythemia – This happens when something else in the body (like chronic lung disease, sleep apnea, or low oxygen at high altitude) triggers the body to make extra red blood cells.

5. Transient or Temporary High Hct – This can occur after a big workout, dehydration, or a hot day when the body loses fluid.

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Diseases or Conditions that Cause High Hematocrit

1. Dehydration – Losing body water makes the blood thicker. Even mild dehydration from not drinking enough water can raise Hct.

2. Chronic Obstructive Pulmonary Disease (COPD) – Lungs don’t take in enough oxygen, so the body produces more red cells.

3. Emphysema – A type of lung damage that leads to chronic low oxygen.

4. Sleep Apnea – Frequent stopping of breathing during sleep lowers oxygen and triggers high Hct.

5. Congenital Heart Disease – Some heart defects cause low oxygen circulation.

6. Pulmonary Fibrosis – Scarring of lung tissue reduces oxygen exchange.

7. Living at High Altitude – The body naturally increases red blood cells when oxygen is scarce.

8. Smoking – Carbon monoxide from smoke blocks oxygen, causing the body to make more red cells.

9. Obesity Hypoventilation Syndrome – Poor breathing patterns due to obesity lead to less oxygen.

10. Kidney Tumors (Erythropoietin Overproduction) – Some kidney tumors produce too much of the hormone EPO, which boosts red cells.

11. Polycystic Kidney Disease – Kidney disorders can increase EPO levels.

12. Anabolic Steroid Use – Steroids can stimulate red cell production.

13. Testosterone Therapy – Testosterone increases red blood cell counts.

14. Polycythemia Vera – A bone marrow disorder that directly raises red cell counts.

15. Heart Failure – The body compensates for low oxygen by making more RBCs.

16. Lung Cancer – Some tumors release chemicals that increase red cells.

17. Severe Burns – Fluid loss from burns makes blood more concentrated.

18. Diuretics Overuse – These medications cause water loss and can fake high Hct.

19. Chronic Stress or Cortisol Imbalance – Stress hormones can affect blood thickness.

20. Severe Vomiting or Diarrhea – Extreme fluid loss reduces plasma volume.

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Symptoms of High Hematocrit

1. Headaches – Thick blood can reduce smooth blood flow to the brain.

2. Dizziness or Lightheadedness – Reduced blood flow and oxygen delivery.

3. Blurred Vision – Tiny blood vessels in the eyes can get clogged.

4. Ruddy or Red Skin Tone – Blood vessels become fuller.

5. Fatigue or Weakness – The heart works harder to pump thick blood.

6. Shortness of Breath – Especially with lung or heart-related causes.

7. High Blood Pressure – Thick blood increases resistance.

8. Itchy Skin (After Hot Showers) – Common in polycythemia vera.

9. Tingling in Fingers or Toes – Due to sluggish circulation.

10. Swelling or Pain in Legs – Blood clots may form more easily.

11. Chest Pain – Strain on the heart due to thick blood.

12. Night Sweats – Sometimes linked to blood disorders.

13. Unexplained Weight Loss – In some cases of cancer or chronic disease.

14. Nosebleeds – Blood vessels can burst under pressure.

15. Confusion or Memory Issues – Reduced blood flow to the brain.

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Diagnostic Tests for High Hematocrit

A. Physical Exams

1. General Physical Examination – A doctor checks skin tone, heart rate, blood pressure, and overall signs of dehydration or illness.

2. Skin and Mucous Membrane Check – Looking for redness, dryness, or blue lips that suggest oxygen problems.

3. Lung and Heart Listening (Auscultation) – Stethoscope exam to detect heart murmurs or lung problems.

B. Manual Tests 

4. Pulse Oximetry – A fingertip sensor measures oxygen saturation.

5. Capillary Refill Test – Pressing on the nail bed to see how fast color returns, indicating blood flow.

6. Orthostatic Vital Signs – Checking blood pressure lying down and standing up to see dehydration effects.

C. Laboratory and Pathological Tests 

7. Complete Blood Count (CBC) – Measures hematocrit, hemoglobin, and red cell count.

8. Blood Smear Test – Checks the shape and size of red blood cells.

9. Erythropoietin (EPO) Level Test – Determines if high Hct is due to hormone overproduction.

10. Arterial Blood Gas (ABG) – Tests blood oxygen and carbon dioxide levels.

11. Serum Ferritin and Iron Tests – Checks iron status; high RBCs need more iron.

12. Kidney and Liver Function Tests – Assesses organs that influence blood production.

D. Electrodiagnostic Tests 

13. Electrocardiogram (ECG) – Looks at heart strain caused by thick blood.

14. Echocardiogram (Echo) – Ultrasound of the heart to check function and oxygen flow.

15. Sleep Study (Polysomnography) – Diagnoses sleep apnea that can raise Hct.

16. Pulmonary Function Tests (PFTs) – Measures lung health and oxygen exchange.

E. Imaging Tests 

17. Chest X-ray – Detects lung disease or heart enlargement.

18. CT Scan (Chest or Abdomen) – Finds tumors or lung damage.

19. MRI of Brain or Heart – Checks for blood flow blockages.

20. Ultrasound of Kidneys – Detects cysts or tumors affecting EPO.

Non-Pharmacological Treatments to Lower Hematocrit

1. Therapeutic Phlebotomy
Description: Routine removal of 300–500 mL of blood every 4–12 weeks.
Purpose: Immediately lowers RBC mass and viscosity.
Mechanism: Reduces total blood volume and iron stores, prompting the body to produce fewer new RBCs, easing circulatory strain.

2. Adequate Hydration
Description: Drinking 2–3 liters of water daily.
Purpose: Dilutes blood plasma to lower relative Hct.
Mechanism: Increases plasma volume, decreasing RBC concentration and improving flow.

3. Regular Aerobic Exercise
Description: 30 minutes of brisk walking, cycling, or swimming most days.
Purpose: Enhances circulation and helps regulate RBC turnover.
Mechanism: Promotes plasma expansion and stimulates healthy endothelial function, preventing excessive RBC production.

4. Weight Management
Description: Achieving a body mass index (BMI) between 18.5–24.9.
Purpose: Lowers inflammation and hormone imbalances that can drive RBC overproduction.
Mechanism: Reduces adipose-derived cytokines (like IL-6) that can stimulate bone marrow RBC synthesis.

5. Smoking Cessation
Description: Quitting tobacco via counseling, nicotine replacement, or medications.
Purpose: Prevents chronic oxygen deprivation that triggers RBC overproduction.
Mechanism: Improves blood oxygen levels, reducing hypoxia-driven erythropoietin (EPO) release from kidneys.

6. Limit Alcohol Intake
Description: No more than 1 drink/day for women and 2 for men.
Purpose: Reduces dehydration and bone marrow stimulation.
Mechanism: Alcohol is a diuretic and can promote dehydration and reactive EPO release.

7. Altitude Avoidance
Description: Minimizing stays above 8,000 feet without acclimatization.
Purpose: Prevents hypoxia-induced RBC overproduction.
Mechanism: At high altitudes, lower oxygen triggers EPO release; staying at lower elevations normalizes EPO.

8. Stress Management (Yoga/Meditation)
Description: 15–20 minutes daily of mindfulness practices.
Purpose: Lowers stress hormones that can influence marrow activity.
Mechanism: Reduces cortisol and catecholamines, which may indirectly affect RBC production.

9. Sauna or Steam Therapy
Description: 10–15 minutes in a sauna 2–3 times weekly.
Purpose: Promotes plasma fluid shifts.
Mechanism: Heat induces sweating and transient plasma volume expansion upon rehydration.

10. Voluntary Blood Donation
Description: Donating whole blood every 8–12 weeks.
Purpose: Similar to phlebotomy, reduces RBC mass.
Mechanism: Removes RBCs and iron, leading to lower Hct and long-term decrease in marrow stimulation.

11. Compression Garments
Description: Graduated compression stockings (20–30 mmHg) for daily wear.
Purpose: Improves venous return, reducing RBC pooling.
Mechanism: Enhances blood flow, preventing stasis and local hypoxia that could trigger RBC overproduction.

12. Intermittent Fasting
Description: 16:8 fasting schedule (16 hours fast, 8 hours eating window).
Purpose: May modestly reduce inflammation and EPO signaling.
Mechanism: Alters metabolic hormones (like insulin) that can influence marrow activity.

13. Plant-Based Diet Focus
Description: Emphasizing fruits, vegetables, whole grains, legumes.
Purpose: Lowers dietary iron intake and inflammation.
Mechanism: Phytates and polyphenols in plants reduce iron absorption and modulate cytokines.

14. Hibiscus Tea Consumption
Description: 2–3 cups/day of hibiscus tea.
Purpose: Natural vasodilator and mild diuretic.
Mechanism: Contains anthocyanins that promote slight fluid loss and reduce plasma viscosity.

15. Deep Breathing Exercises
Description: 5 minutes of diaphragmatic breathing twice daily.
Purpose: Improves oxygenation, reducing EPO drive.
Mechanism: Maximizes lung expansion and oxygen uptake, lowering hypoxic stimulus.

16. Sleep Hygiene Optimization
Description: 7–9 hours of quality sleep nightly.
Purpose: Balances hormones and reduces stress.
Mechanism: Proper rest normalizes cortisol and EPO secretion rhythms.

17. Acupuncture
Description: Weekly sessions for 4–6 weeks.
Purpose: Potentially modulates autonomic and endocrine pathways.
Mechanism: May influence hypothalamic-pituitary axis and reduce stress-induced EPO release.

18. Chelation for Heavy Metals
Description: Under specialist supervision, chelating agents for heavy metal removal.
Purpose: Reduces marrow-stimulating toxins.
Mechanism: Binds metals (lead, arsenic) that can cause marrow irritation and polycythemia.

19. Avoid Dehydrating Environments
Description: Use humidifiers in dry climates and take regular fluid breaks.
Purpose: Maintains plasma volume to keep Hct lower.
Mechanism: Prevents fluid shifts that concentrate RBCs.

20. Mind–Body Therapies (Tai Chi)
Description: 30 minutes of Tai Chi practice 3 times/week.
Purpose: Enhances circulation and stress reduction.
Mechanism: Smooth movements improve blood flow and mitigate sympathetic overdrive.

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Key Drugs to Lower Hematocrit

1. Hydroxyurea

• Class: Antimetabolite

• Dosage: 15–20 mg/kg once daily, adjust to maintain Hct <45%

• Timing: Oral, morning with food

• Side Effects: Bone marrow suppression (anemia, leukopenia), gastrointestinal upset, hair thinning

2. Interferon Alfa-2a

• Class: Immunomodulator

• Dosage: 3 million IU subcutaneously thrice weekly

• Timing: Morning or evening, consistent schedule

• Side Effects: Flu-like symptoms, fatigue, depression, myalgia

3. Peginterferon Alfa-2a

• Class: Pegylated interferon

• Dosage: 45–135 µg subcutaneously once weekly

• Timing: Any time of day, day-of-week consistency

• Side Effects: Injection-site reactions, neutropenia, mood swings

4. Ruxolitinib

• Class: JAK1/2 inhibitor

• Dosage: 10–20 mg twice daily based on platelet count

• Timing: Morning and evening with meals

• Side Effects: Thrombocytopenia, anemia, infections

5. Fedratinib

• Class: JAK2 inhibitor

• Dosage: 400 mg once daily

• Timing: Morning with food

• Side Effects: Gastrointestinal symptoms, Wernicke encephalopathy risk (monitor thiamine)

6. Momelotinib

• Class: JAK1/2 inhibitor

• Dosage: 200 mg once daily

• Timing: Morning

• Side Effects: Anemia, diarrhea, peripheral neuropathy

7. Givinostat

• Class: Histone deacetylase inhibitor

• Dosage: 50 mg twice daily

• Timing: With meals

• Side Effects: Diarrhea, thrombocytopenia, fatigue

8. Pipobroman

• Class: Alkylating agent

• Dosage: 5 mg once daily

• Timing: Morning

• Side Effects: Leukopenia, risk of secondary leukemia

9. Busulfan

• Class: Alkylating agent

• Dosage: 2–4 mg orally daily for 4–6 weeks

• Timing: Morning

• Side Effects: Pulmonary fibrosis, seizures (prophylaxis with anticonvulsants recommended)

10. PTG-300 (Rusfertide)

• Class: Hepcidin mimetic (investigational)

• Dosage: 10 mg subcutaneously weekly

• Timing: Any consistent day

• Side Effects: Injection-site reactions, arthralgia

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Dietary Molecular Supplements

1. Curcumin (Turmeric Extract)

• Dosage: 500 mg twice daily

• Function: Anti-inflammatory antioxidant

• Mechanism: Inhibits NF-κB and reduces cytokine-driven RBC production

2. Resveratrol

• Dosage: 250 mg once daily

• Function: Vasodilator, antioxidant

• Mechanism: Activates SIRT1, improving endothelial function and decreasing marrow stimulation

3. Omega-3 Fatty Acids

• Dosage: 2 g EPA/DHA daily

• Function: Anti-inflammatory lipid

• Mechanism: Reduces pro-inflammatory eicosanoids that can drive erythropoiesis

4. Aged Garlic Extract

• Dosage: 600 mg daily

• Function: Blood viscosity reducer

• Mechanism: Inhibits platelet aggregation and promotes mild vasodilation

5. Green Tea Extract (EGCG)

• Dosage: 300 mg once daily

• Function: Antioxidant and diuretic

• Mechanism: Catechins reduce iron absorption and promote mild fluid loss

6. Vitamin C

• Dosage: 500 mg once daily

• Function: Antioxidant

• Mechanism: Enhances endothelial health and iron metabolism

7. Vitamin E

• Dosage: 400 IU once daily

• Function: Membrane stabilizer

• Mechanism: Protects RBCs from oxidative damage, indirectly modulating turnover

8. Quercetin

• Dosage: 500 mg twice daily

• Function: Anti-inflammatory flavonoid

• Mechanism: Inhibits mast cell degranulation and reduces cytokine release

9. Ginkgo Biloba

• Dosage: 120 mg daily

• Function: Vasodilator

• Mechanism: Increases nitric oxide, improving flow and decreasing hypoxia signaling

10. Nattokinase

• Dosage: 2,000 FU daily

• Function: Fibrinolytic enzyme

• Mechanism: Breaks down fibrin, reducing blood viscosity and clot risk

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Advanced Immunomodulatory & Regenerative Therapies

1. Ropeginterferon Alfa-2b

• Dosage: 250–500 µg subcutaneously every 2 weeks

• Function: Long-acting immunomodulator

• Mechanism: Sustained EPO suppression and marrow regulation

2. High-Dose Interferon Alfa-2a

• Dosage: 9 million IU thrice weekly

• Function: Potent antiviral/immunoregulatory

• Mechanism: Strong inhibition of JAK–STAT signaling in progenitor cells

3. Ruxolitinib (High Intensity)

• Dosage: Up to 25 mg twice daily (for resistant cases)

• Function: JAK inhibition

• Mechanism: Blocks pathologic JAK2-driven erythropoiesis

4. Fedratinib (Escalated Dose)

• Dosage: 500 mg once daily

• Function: JAK2 selectivity

• Mechanism: Reduces spleen size and marrow overactivity

5. Busulfan (Myeloablative)

• Dosage: 3.2 mg/kg IV over 4 days (conditioning)

• Function: Myeloablation for stem cell transplant

• Mechanism: Destroys marrow to allow engraftment of healthy stem cells

6. Allogeneic Stem Cell Transplant

• Procedure: Single infusion after myeloablative regimen

• Function: Curative replacement of diseased marrow

• Mechanism: Donor stem cells reconstitute healthy erythropoiesis

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Prevention Strategies

1. Routine Health Check-Ups: Annual blood counts to catch rising Hct early.

2. Treat Underlying Lung Disease: Optimize COPD or sleep apnea to prevent hypoxia-driven RBC increase.

3. Avoid Anabolic Steroids/Testosterone: These can spur RBC overproduction.

4. Maintain Optimal Hydration: Steady fluid intake prevents hemoconcentration.

5. Control Blood Pressure: Hypertension worsens vascular stress in high viscosity states.

6. Quit Smoking: Stops chronic hypoxia stimulus.

7. Balanced Diet: Moderate iron intake and focus on anti-inflammatory foods.

8. Stress Reduction: Chronic stress can subtly drive marrow activity.

9. Exercise Regularly: Keeps plasma volume robust.

10. Monitor Altitude Exposure: Acclimatize slowly if travel to high elevations.

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When to See a Doctor

Seek medical attention if you experience any of the following alongside known or suspected moderate high Hct (≥52% in men, ≥48% in women):

• Unexplained Headaches or Dizziness: Could signal poor cerebral perfusion.

• Blurred Vision or Tinnitus: Signs of high blood viscosity.

• Chest Pain or Palpitations: Risk of cardiac strain or clot.

• Erythromelalgia (Burning Pain in Hands/Feet): Small-vessel clots.

• Itchy Skin, Especially After Warm Shower: Mast cell release from elevated RBCs.

• Persistent Fatigue or Weakness: Indicates tissue hypoxia despite high RBC count.

• Uncontrolled Hypertension: May need Hct-directed therapy.

• Recurrent Nosebleeds or Bleeding Gums: Paradoxical bleeding risk despite clotting tendency.

• Shortness of Breath at Rest: Worrisome for pulmonary hypertension.

• Any New Neurologic Symptoms: Risk of stroke or transient ischemic attack.

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Foods to Eat and to Avoid

Eat:

1. Cucumber & Watermelon: High water content to boost plasma volume.

2. Leafy Greens (Spinach, Kale): Contain phytates to reduce iron absorption.

3. Berries (Blueberries, Strawberries): Rich in antioxidants to protect vessels.

4. Beetroot Juice: Contains nitrates that improve blood flow.

5. Oily Fish (Salmon, Mackerel): Provide omega-3s to reduce inflammation.

6. Nuts & Seeds: Contain healthy fats and minerals promoting circulation.

7. Whole Grains: Offer fiber and phytates for balanced iron levels.

8. Legumes (Lentils, Beans): Plant-based protein with low heme iron.

9. Citrus Fruits: Vitamin C for endothelial health.

10. Green Tea: Mild diuretic and catechin source.

Avoid:

1. Red Meat & Organ Meats: High heme iron raises Hct.

2. Iron-Fortified Cereals: Can unintentionally boost iron stores.

3. Alcohol (Especially Beer): Promotes dehydration and marrow stimulation.

4. Smoked or Cured Meats: Nitrates and advanced glycation products.

5. High-Salt Processed Foods: Raise blood pressure and fluid shifts.

6. Energy Drinks & High-Caffeine Beverages: Diuretic effect can concentrate Hct.

7. Sugary Snacks: Promote inflammation and endothelial dysfunction.

8. Dried Fruits (Ex: Apricots, Raisins): Extremely concentrated iron source.

9. Vitamin C Supplements with Meals: Increases iron uptake when taken with iron-rich foods.

10. Excessive Vitamin B12 or Folate Supplements: Can support excessive RBC production if unneeded.

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Frequently Asked Questions

1. What exactly is a moderate high hematocrit?
Moderate high Hct means your red blood cells make up about 52–60% of your blood volume (men) or 48–60% (women), which is above normal but below severe levels.

2. How is hematocrit measured?
A simple blood draw analyzed by an automated cell counter or manual centrifuge yields the percentage of RBCs in blood.

3. Why does my hematocrit rise?
Common causes include dehydration, smoking, living at high altitude, lung disease, and rare marrow disorders like polycythemia vera.

4. Can dehydration alone cause moderate high Hct?
Yes—if you lose plasma fluid (through sweating or diarrhea) without replacing it, your Hct will appear elevated until rehydration.

5. How fast can I lower hematocrit with phlebotomy?
One 500 mL phlebotomy session typically reduces Hct by 3–5 percentage points almost immediately.

6. Are there natural ways to lower my Hct?
Yes—staying well-hydrated, quitting smoking, exercising moderately, and eating a plant-based diet can all help.

7. When should I start drug therapy for high Hct?
If non-pharmacological measures and phlebotomy can’t keep Hct below 50–52%, or if you have symptoms or clotting risk, your doctor may start drugs like hydroxyurea.

8. What are the side effects of hydroxyurea?
Common issues include mild anemia, low white cell counts, nausea, and temporary hair thinning; serious risks are rare with proper monitoring.

9. Can supplements replace medication?
Supplements like curcumin or green tea extract can support healthy blood flow but aren’t a substitute for drugs if you have a marrow disorder driving Hct up.

10. Is polycythemia vera the only cause of moderate high Hct?
No—secondary causes like lung disease, sleep apnea, tumors producing EPO, and dehydration are more common.

11. How often should I check my hematocrit?
Generally every 3–6 months if stable; more often (monthly) if you’re adjusting treatments.

12. Can high Hct cause blood clots?
Yes—thicker blood flows more slowly and is more prone to clotting in veins and arteries.

13. Is it safe to travel to high altitudes?
If you have moderate high Hct, talk to your doctor; you may need extra monitoring and supplemental oxygen.

14. Will allogeneic stem cell transplant cure high Hct?
In rare, severe cases (e.g., young patients with polycythemia vera), transplant can be curative but carries significant risks.

15. Can I prevent high Hct with diet alone?
A balanced diet low in heme iron and rich in hydrating, anti-inflammatory foods helps, but monitoring and sometimes medical therapy are also needed.

Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical  history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.

The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members

Last Updated: July 26, 2025.