Plantar fasciitis is one of the most common causes of heel pain, arising from irritation and degeneration of the thick band of tissue running across the bottom of the foot, connecting the heel bone to the toes. It typically causes a sharp, stabbing pain, particularly with the first steps after waking up or following a period of rest. Because these symptoms are easily recognizable, many people self-diagnose, but this approach often overlooks other serious conditions that mimic the pain. Heel pain can point to a number of distinct injuries and disorders, and confusing the true cause can lead to ineffective treatment. Understanding the specific characteristics of these “imposter” conditions is essential for achieving correct diagnosis and lasting relief.
Conditions Involving Nerve Entrapment and Referred Pain
One group of conditions often mistaken for plantar fasciitis involves the compression or irritation of nerves in the ankle or lower back. Tarsal Tunnel Syndrome (TTS) is a prime example, where the posterior tibial nerve is compressed as it passes through a narrow passageway on the inside of the ankle. This nerve compression causes pain that can radiate to the heel and arch, similar to plantar fasciitis.
TTS typically involves burning, tingling, or numbness, known as paresthesia, which is not a common feature of true plantar fasciitis. While plantar fasciitis pain is often worst with initial steps, TTS pain may persist even at rest or worsen with activity, reflecting the nerve’s irritation. Tapping near the nerve path, known as Tinel’s sign, can also reproduce the tingling.
Referred pain from the lower spine, specifically lumbar radiculopathy involving the L5 or S1 nerve roots, can also project pain down to the heel. This occurs when a herniated disc or spinal stenosis compresses a nerve in the back, causing pain to travel along the nerve pathway to the foot. This type of referred heel pain may be accompanied by symptoms elsewhere in the leg, such as lower back pain, weakness, or radiating sensations down the calf, which clearly distinguishes it from a localized foot issue. Nerve-related heel pain that does not respond to typical foot treatments should prompt an investigation of the spine as the source.
Mistaken Diagnoses Related to Bone Structure and Integrity
Pain originating directly from the calcaneus, or heel bone, can be easily confused with the ligamentous pain of plantar fasciitis. A calcaneal stress fracture is a tiny crack in the bone resulting from repetitive impact. Unlike plantar fasciitis, where pain is focused at the fascia’s attachment point on the medial side of the heel, stress fracture pain is often localized directly to the bone and tends to be constant.
The pain from a stress fracture worsens with weight-bearing and may be present at night. Applying pressure directly to the sides of the heel bone often triggers sharp pain in a stress fracture. Imaging tests like X-rays or an MRI are typically necessary to confirm a stress fracture, as its underlying cause is structural damage to the bone itself.
Inflammatory types of arthritis can also cause heel pain that mimics plantar fasciitis. These conditions often cause enthesitis, which is inflammation where tendons and ligaments attach to the bone. This inflammatory pain is often bilateral, affecting both feet, and may be accompanied by systemic symptoms like joint stiffness and pain in other areas of the body. Unlike mechanical pain, arthritic pain may improve with activity rather than rest, distinguishing it from the typical presentation of plantar fasciitis.
Soft Tissue and Degenerative Causes of Heel Pain
Heel pad atrophy, the thinning or degeneration of the protective fat pad under the heel, is the second leading cause of plantar heel pain after plantar fasciitis. This condition reduces the natural cushioning and shock absorption provided by the fat pad.
Pain from heel pad atrophy is often described as a deep ache or bruise-like sensation, typically felt in the central part of the heel. The pain is aggravated by prolonged standing or walking, especially on hard surfaces, and notably lacks the sharp “first step” pain characteristic of plantar fasciitis. Treatment for this condition focuses on external cushioning and support, as stretching the fascia is not the appropriate approach.
Bursitis around the heel can also cause localized inflammation and pain. Retrocalcaneal bursitis involves the bursa located between the Achilles tendon and the heel bone. The pain is focused on the posterior aspect of the heel, distinct from plantar fasciitis pain, which is concentrated on the sole of the foot. Similarly, Achilles tendinopathy, or degeneration of the Achilles tendon, causes pain and stiffness higher up on the back of the heel and ankle. The pain is not primarily on the bottom of the foot.