There are several diseases that can cause severe foot pain. According to the U.S. Library of Medicine and the National Institutes of Health (NIH), pain or discomfort can manifest in any part of the foot, including a person's heel, midfoot and forefoot. The NIH states that poorly fitting shoes may be responsible for a significant amount of foot pain, although certain medical conditions also can arise in the foot and cause severe pain.
Plantar Fasciosis
Plantar fasciosis is a disease associated with severe foot pain. According to the Merck Manuals website, plantar fasciosis is pain on the foot's underside, where the plantar fascia--a thick band of connective tissue that supports the foot's arch--attaches to the calcaneus, or heel bone. A person with plantar fasciosis also may experience pain or discomfort on the medial or inside edge of her foot. Pain in the plantar fascia also has been called plantar fasciitis; however, because there usually is no inflammation present in the plantar fascia, the term plantar fasciosis is more appropriate.
Plantar fasciosis is characterized by pain on the underside of the foot during weight-bearing activities. The pain often is worse in the morning and returns later in the day. Plantar fasciosis-related pain can range from mild to severe. Severe heel pain that arises suddenly may be indicative of a tear in the plantar fascia, especially if there is swelling in the affected area.
Podagra
The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a division of the NIH, states that when gout affects the joints of the big toe, the condition is called podagra. Gout is a painful condition caused by the deposition of uric acid crystals in a person's joints or soft tissues. The uric acid crystals cause inflammatory arthritis that leads to swelling, redness, heat and pain in the affected area. The big toe is one of the most common initial locations for gout to manifest. Gout also is common in the ankles, heels, knees, wrists, fingers and elbows. Gout has numerous risk factors, including genetics, gender, age, excessive weight, excessive alcohol consumption, high-purine foods, lead exposure and certain health problems and medications.
Trench Foot
According to the Centers for Disease Control and Prevention (CDC), trench foot, also known as immersion foot, manifests when a person's feet are wet for prolonged periods of time. The CDC states that although trench foot can cause severe foot pain, it is preventable and treatable. Common trench foot-related signs and symptoms include numbness, tingling or itching in the feet, pain, swelling, cold and patchy skin and a heavy sensation in the foot. Foot blisters are common in a person with trench foot; blisters may be followed by tissue death and sloughing in the affected area. In some people, especially those with severe cases of trench foot, the disease can affect the toes, heel or the entire foot.
People can prevent and treat trench foot by elevating and air-drying the feet as often as possible, along with swapping wet shoes and socks for dry ones. A person working in a moist, damp environment should check his feet at least once per day for signs of foot infection, the CDC notes.
