Plantar fasciitis is usually diagnosed by clinical findings alone; if characteristic signs and symptoms are present the diagnosis is likely to be accurate.

• Ask about the nature of the heel pain, and the general health and physical activity of the person.
• Characteristic symptoms of plantar fasciitis include:
• An initial insidious onset of pain.
• Intense pain during the first steps after waking or after a period of inactivity.
• Lessening pain with moderate foot activity, but worsening later during the day or after long periods of standing or walking.
• Plantar fasciitis typically affects people 40–60 years of age who are overweight or obese, or who are on their feet for extended periods. Conversely, it may affect younger people who engage in sporting activities (e.g. running).
• Examine the foot at rest (when sitting), and when standing and walking.
• Tenderness on palpation of the plantar heel area (particularly, but not always, localized around the medial calcaneal tuberosity) is a defining sign of plantar fasciitis.
• Limited ankle dorsiflexion range (with the knee in extension) and a positive 'Windlass test' (reproduction of pain by extension of the first metatarsophalangeal joint) is suggestive of plantar fasciitis.
• An antalgic gait (abnormal walking to avoid pain) or limping may be observed.
• If clinical signs of plantar fasciitis are absent or inconsistent, consider an alternative diagnosis.
• Ask about recent or past trauma and recent changes in footwear, to rule out conditions such as fractures and sub-calcaneal bursitis.
• Examine the foot for physical abnormalities, including congenital abnormalities such as pes planus (flat foot) or pes cavus (high arch), tight Achilles tendon or signs of tendonitis, or skin changes which may indicate systemic disorders or infection.
• Investigation is only required to exclude alternative diagnoses.
• Consider testing for erythrocyte sedimentation rate, C-reactive protein, and Human Locus Antigen B27 for spondyloarthropathies, and referral to radiography for fractures.
• Bilateral plantar fasciitis is estimated to occur in up to 30% of people with the condition, but nevertheless should increase the degree of suspicion that there may be a systemic cause.

These recommendations are based on an American evidence-based guideline [McPoil et al, 2008], a UK guideline [ARC, 2004a], an electronic guideline [Foye and Stitik, 2008], and a narrative review [Neufeld, 2008].

• A systematic review (search date: August 2005) identified increased weight (in a non-athletic population), increased age, and prolonged standing, as risk factors associated with plantar fasciitis [Irving et al, 2006].
• A positive clinical history and examination will successfully diagnose most cases of plantar fasciitis; plantar fasciitis accounts for 80% of cases of heel pain, and symptoms and signs taken together are sensitive and specific.
• First-step heel pain on waking is very common, as the plantar fascia contracts during rest and sleep, leading to stiffness and pain upon subsequent weight-bearing.
• The Windlass test is highly specific for plantar fasciitis, but not very sensitive, making it a suitable tool for confirming diagnoses rather than for screening.
• Investigations are generally not useful for diagnosing plantar fasciitis (such as the presence of a calcaneal spur is not now believed to be a key radiographic feature of plantar fasciitis) [ARC, 2004a].

• If characteristic symptoms and signs are not consistent with plantar fasciitis, consider:
• Calcaneal stress fracture, which typically presents with diffuse, warm swelling, and can be diagnosed by squeezing the calcaneum, inducing pain. It is confirmed by radiography, although changes may be subtle or even absent.
• Achilles tendonitis may present with tenderness on palpation, and pain radiating up the calf with extension of the foot or standing on tiptoes (complete rupture causes severe pain and loss of foot stability). Flexor hallucis or posterior tibial tendonitis may also mimic plantar fasciitis.
• Fat pad atrophy causes centralized heel pain, and a flattened atrophied surface may be felt on palpation.
• Sub-calcaneal bursitis typically affects obese people or athletes, and presents as posterior heel pain under the fat pad of the calcaneum.
• Other causes less likely to be misdiagnosed as plantar fasciitis include:
• Neurological causes:
• Tarsal tunnel syndrome, which is detected by a positive 'Tinel's sign' on a dorsiflexed, everted foot (often missed in primary care).
• S1 radiculopathy causes pain that radiates throughout the leg. It can be ruled out by a comprehensive neurological examination.
• Nerve entrapment (such as lateral plantar and medial nerves) can mimic plantar fasciitis, but tends not to specifically affect the medial tuberosity. In particular, the first branch of the lateral plantar nerve may present with tenderness on the medial side of the edge of the heel, with pain radiating to the lateral side of the heel.
• Peripheral neuropathy lacks a specific focal area of pain and sensations may still be felt at rest.
• Other musculoskeletal causes:
• Plantar fascia rupture, which presents as a sudden onset of pain. There may be a palpable gap and evidence of collapse in the medial and longitudinal arches.
• Plantar fibromatosis causes pain in the mid-section of the plantar fascia and palpable nodules.
• Bone contusion typically affects obese people or athletes, and presents as posterior heel pain under the fat pad of the calcaneum.
• Infection (osteomyelitis or subtalar pyoarthrosis) is rare in the absence of an open wound. It presents with a red, hot, swelling and systemic illness.
• Subtalar arthritis usually presents with pain felt in the subtalar joint (i.e. deep within the heel) upon weight bearing.
• Inflammatory arthropathies and gout can be ruled out by appropriate investigations.
• Neoplasm and vascular insufficiency are very rare causes of heel pain (but should be considered in recalcitrant cases).

These recommendations are based on an American evidence-based guideline [McPoil et al, 2008], a UK guideline [ARC, 2004a], and a narrative review [Neufeld, 2008].