What Is the Main Cause of Plantar Fasciitis?

Plantar fasciitis typically develops without a specific cause. Risk factors include repetitive impact to the heel (running, dancing, other sports), improper athletic training, new or increased activity, obesity, being female, wearing high heels, occupations requiring prolonged standing and weight-bearing, limited ankle flexibility, tight hamstrings/glutes/calf muscles, structural problems with the foot/ankle, and others.
Plantar fasciitis typically develops without a specific cause. Risk factors include repetitive impact to the heel (running, dancing, other sports), improper athletic training, new or increased activity, obesity, being female, wearing high heels, occupations requiring prolonged standing and weight-bearing, limited ankle flexibility, tight hamstrings/glutes/calf muscles, structural problems with the foot/ankle, and others.

Plantar fasciitis is inflammation and pain in the heel area caused by irritation at the insertion of the fascia, a thick band of fibrous connective tissue at the bottom of the foot that runs from the heel to the toes. It is the most common cause of pain on the bottom of the heel. 

It is a common condition sometimes called jogger’s heel, tennis heel, or policeman’s heel, and may be incorrectly referred to as heel spurs. Plantar fasciitis occurs when the plantar fascia — a thick band of fibrous connective tissue at the bottom of the foot that runs from the heel to the toes — is overly stretched and tears.

What Are the Causes of Plantar Fasciitis?

Most of the time, plantar fasciitis develops without a specific cause. 

Risk factors for stretching and tearing the plantar fascia include:

  • Participating in activities that cause repetitive impact to the heel such as running, dancing, and other sports
    • Plantar fasciitis is common in runners and it may be due to:
      • Overtraining or sudden increases in distance
      • Poorly fitted running shoes/worn out shoes (runners should replace shoes every 250-500 miles)
      • Running on hard surfaces (concrete is harder than pavement, which is harder than dirt)
      • Flat feet
      • High arches
  • Improper athletic training
  • New or increased activity
  • Obesity
  • Being female
  • Wearing high heels 
  • Occupations requiring prolonged standing and weight-bearing 
  • Limited ankle flexibility
  • Tight hamstrings or glutes
  • Tight calf muscles that make it difficult to flex the foot and bring the toes up toward the shin
  • Structural problems with the foot/ankle: high or low arches, overpronation, leg-length differences, excessive lateral tibial torsion, and excessive femoral anteversion
  • Aging and heel fat pad atrophy
  • Rheumatic disorders such as ankylosing spondylitis or psoriatic arthritis

What Are Symptoms of Plantar Fasciitis?

The main symptom of plantar fasciitis is pain beneath the heel on the bottom of the foot. Pain may occur in one or both feet. 

  • The pain may be sharp and severe
  • It is usually worse in the morning or after sitting for long periods
  • Pain tends to improve with activity but will worsen again after long periods on your feet
  • Pain is worse after (not during) exercise or activity
  • Limping

How Is Plantar Fasciitis Diagnosed?

A doctor will take a medical history and perform a physical exam of the feet. No specific lab tests or imaging studies are needed to diagnose plantar fasciitis but they may be used to rule out other causes of heel pain such as fractures, tumors, or arthritis

Imaging tests may include:

Blood tests may include:

What Is the Treatment for Plantar Fasciitis?

More than 90% of patients with plantar fasciitis will improve within 10 months using conservative treatment methods that include:

  • Rest
    • Stopping or limiting activities where there is repetitive heel impact or that worsen pain
  • Ice
    • Ice the area for 20 minutes up to four times daily, to help relieve pain
    • Try rolling your foot over a frozen water bottle
  • Stretching exercises 
    • Tight muscles in the feet and calves can aggravate plantar fasciitis
  • Over-the-counter (OTC) pain medications 
  • Wear protective footwear for temporary pain relief
    • Athletic shoes
    • Arch-supporting shoes
    • Shoes with rigid shanks
    • Cushion-soled shoes with gel pad inserts or heel cups 
  • Orthotics to properly support the foot may help 
  • Tape the foot with a technique called "low-Dye taping" 
  • Splints worn overnight may be helpful to provide pain relief and a gentle stretch
  • Avoid wearing slippers or going barefoot

If conservative measures do not relieve the pain caused by plantar fasciitis, other treatments include: 

  • Physical therapy for long-term pain relief
  • Steroid injections in the foot to relieve pain
    • The effect may wear off in a few weeks
  • Botulinum toxin type A injection 
    • May help with pain relief and overall foot function
  • Walking cast
  • Surgery is rarely needed for plantar fasciitis and is only recommended when all other treatments have failed symptoms persist for at least 6 to 12 months
    • Fasciotomy surgery involves detaching the plantar fascia from the heel bone
    • Cryosurgery destroys damaged tissue
    • Bipolar radiofrequency microdebridement applies a bipolar radiofrequency pulse to the plantar fascia
  • Autologous blood injection, platelet-rich plasma (PRP) injection, nitroglycerin patches, and extracorporeal shock-wave therapy (ESWT) are treatments designed to create an acute inflammatory reaction and restart the healing process
  • Extracorporeal shock wave therapy (ESWT) has not yet been shown to be effective, but it is approved by the Food and Drug Administration (FDA) to treat plantar fasciitis and may be recommended by some clinicians
References
http://emedicine.medscape.com/article/86143-overview

https://www.uptodate.com/contents/heel-and-foot-pain-caused-by-plantar-fasciitis-beyond-the-basics?search=Plantar%20Fasciitis&source=search_result&selectedTitle=2~41&usage_type=default&display_rank=2

https://orthoinfo.aaos.org/en/diseases--conditions/plantar-fasciitis-and-bone-spurs