What is Corns?
A corn, also known by other medical terms such as “clavus,” “heloma,” or “focal intractable plantar hyperkeratosis,” is a type of hard skin buildup. Corns are areas of thick, painful skin that form due to frequent rubbing or pressure. The medical community often uses multiple terms to describe various types of hard skin buildups, which can be confusing.
However, healthcare professionals must understand the difference between a corn and a callus. A callus is a more spread out area of hard skin, while a corn is a well-defined area of extremely hard skin. Corns are commonly found in sportspeople and in individuals who experience uneven rubbing from shoes or walking issues, including older adults, individuals with diabetes, and amputees. It’s important to note that a corn isn’t a disease in itself, but rather a symptom of continual friction or pressure on the skin.
What Causes Corns?
Corns usually develop due to regular build-up of damage from things like wearing shoes that don’t fit properly, having a deformity in the foot which causes bony bumps, or specific physical activities. They are most often found on the feet, specifically on the tops of the toes, between the last two toes, and on the soles of the feet.
Risk Factors and Frequency for Corns
Corns on the feet are quite common, with their occurrence ranging from 14% to 48% in different reports. People with darker skin tones are more likely to develop corns. It’s also known to affect older individuals more frequently, especially females who wear narrow shoes. Additionally, elderly people are often affected due to a condition known as fat pad atrophy, where they lose protective cushioning. This can make corns on the feet more painful.
- Corns on the feet occur in about 14% to 48% of people according to various reports.
- They are more common in individuals with darker skin tones.
- Older people, especially females who wear narrow shoes, are more prone to developing corns.
- Elderly people can suffer more from corns due to a condition known as fat pad atrophy, which causes a loss of protective cushioning in the foot.
Signs and Symptoms of Corns
Corns are usually diagnosed by assessing a person’s skin and noticing how their body reacts to physical damage. They can easily be identified by their hard, rough texture and the specific areas they usually appear on the body. The individual’s physical activity history can also provide useful information.
Corns look like dry, hard, and rough bumps with a white center on the skin, usually over a bony part of the foot. They cause pain while walking and standing, but not when touched. The buildup and thickening of keratin, a skin protein, can make the corns grow larger and cause significant discomfort when moving.
- Hard corn (“heloma durum”) – This is the most common type of corn that usually shows up on the side and top of the fifth toe or on the top of the smaller toes’ joints.
- Soft corn or interdigital corn (“heloma molle”) – This painful corn predominantly appears in the areas between the toes, especially the fourth space, causing the skin to become macerated. This location can often lead to bacterial or fungal infections or ulcers.
Some medical professionals point out a third type of corn known as seed corn. Seed corns are multiple non-painful, hard skin plugs within the calluses on the bottom of the foot where there is no pressure.
It can sometimes be challenging to distinguish between corns and plantar warts. For instance, with corns, skin lines within the lesions can be seen, unlike plantar warts. Also, if pressure is applied to the plantar corn, it will come into contact with the bone underneath, causing pain. This is not the case with warts. A distinguishing feature of corns is the absence of capillary dotting or “Auspitz’s sign” after the hard layer of skin is removed. Dermoscopy, a skin surface microscopy technique, can also help differentiate between corns and plantar warts.
Testing for Corns
Dermoscopy is a tool that can aid in diagnosing corns by highlighting areas of thickened skin, without the blood vessels or bleeding typically associated with warts.
Additionally, foot X-rays can be beneficial. They can show if any bone bulges are leading to the formation of corns.
Pressure studies of the feet can also be useful. These tests can pinpoint areas on the soles of the feet where pressure is too high, often a common factor in the development of corns on the bottom of the feet.
In some cases, other tests like a fasting glucose test or a rheumatoid factor test may be ordered. These can help determine if a foot deformity, potentially leading to corns, is caused by conditions such as diabetes or rheumatoid arthritis.
Treatment Options for Corns
Treatment for corns on your feet aims to reduce pain and discomfort. The healthcare provider will carefully trim or shave the corn without causing bleeding using a scalpel. They might also remove a central hard core from the corn after numbing the area, which then eases pressure on the skin and underlying nerves and reduces pain. Patients should soak their feet in warm water for twenty minutes and gently trim the corn each week with a pumice stone or foot file.
If you have diabetes and might not feel much sensation in your feet, it’s safer to have a foot care specialist (podiatrist) trim the corn, as you could inadvertently cut your skin if you do it yourself.
Topical medications can also help treat corns. One example is salicylic acid, which comes in a pad or solution, and comes in strengths between 12.6% to 40%. A study once found salicylic acid to be more effective than shaving the corn in reducing corn size, pain, and delaying its reappearance. Other beneficial treatments can include urea (20% to 50%), silver nitrate, and medicated dressings.
Some healthcare providers might recommend laser therapy to treat corns. This could involve using a carbon dioxide laser or a special type of laser called an erbium-doped yttrium aluminum garnet laser, which causes minimal thermal tissue damage. The downside is that if you continue to wear the same type of footwear that caused the corn, it may come back. Controlling any misalignments or deformities in your feet and wearing appropriate footgear with soft cushions can help manage corns by reducing friction and increasing comfort.
Avoiding poorly fitted shoes and any other kinds of mechanical pressure on your feet can prevent corns.
If other treatments do not work, surgery to correct underlying bone issues may be needed. For instance, surgery can help with a condition called ‘hammertoe’, where a toe is bent in an abnormal position. Removing a small piece of bone from the toe can release the tightness and reduce the pressure that leads to corns.
In the case of a soft corn formation in between the fourth and fifth toe, a surgical procedure to fuse the soft tissue of the adjacent toes, called syndactylization, can help. This procedure involves removing the adjacent skin surfaces between the fourth and fifth toes, helping them stay close to each other, and prevent recurrent soft corns. This surgery is often used in combination with a procedure on the fifth toe in the treatment of the soft corn.
What else can Corns be?
If you have a corn, your doctor might have to consider other conditions that have similar features. These could include:
- Plantar warts, which are small growths on the feet
- Poroma, a kind of skin tumour
- Warty dyskeratoma, an unusual skin lesion
- Calcinosis cutis, a condition where calcium deposits form in the skin
- Gout and pseudogout, which are kinds of arthritis
- Hypertrophic lichen planus, a skin disease that causes lesions
- Interdigital neuroma, a nerve problem in the foot
- Lichen simplex chronicus, a skin disorder resulting in chronic itching
- Palmoplantar keratoderma, a skin disorder causing thick skin on the hands and feet
- Keratosis punctata of the palmar creases, which leads to small, rough bumps
- Porokeratosis plantaris discreta, a skin condition causing calluses
- Porokeratosis palmoplantar et disseminata, a rare skin disorder causing red patches and lines
It’s necessary for your doctor to consider all these possibilities to correctly diagnose your condition.
What to expect with Corns
Corns and calluses are long-lasting issues that often come and go. They usually get better on their own when the pressure or rubbing causing them stops. However, if corns persist or start to cause intense pain, it’s advisable to consult a foot doctor, or podiatrist.
A small study from 2021, involving 39 patients, compared surgical treatment with non-surgical remedies. They found that all patients who got surgery reported excellent satisfaction level, compared to only around 29% of patients who used non-surgical methods. The study also showed high patient satisfaction rates, with 93% of patients – 62 feet in all – reporting relief from pain after surgery to fix corns on the 4th and 5th toes.
Possible Complications When Diagnosed with Corns
Problems that can arise from corns are:
- Ulceration and infection
- Pain
- Fungal infection of the foot (Tinea pedis)
- Septic arthritis – infection in a joint
- Osteomyelitis – infection in the bone
Following a surgical remedy for corns, some people may experience:
- Stiffness in joints and toes
- Swelling in the toes
- Numbness
- Infection
- Floppy or uncontrolled toe movement
- Deformed toe returning
Recovery from Corns
After most surgeries for corns, patients are typically allowed to put as much weight as they can tolerate on the foot, while wearing a special surgical shoe. The duration for wearing this shoe can vary from two to six weeks, depending on the exact surgery performed. Generally, patients should avoid removing the bandages or getting the foot wet.
It’s normal to experience pain during recovery and pain relief medication might be needed for the first few days. If the surgery was on the right foot, patients are advised not to drive. The stitches from the surgery are usually taken out about two weeks post-surgery. Most of the time, physical therapy isn’t necessary after this type of surgery.
Preventing Corns
Corns are thick skin spots that usually form on the toes because of consistent rubbing or pressure, often caused by shoes. They differ from calluses in one major way – inside a corn, there’s a hardened core. Certain foot conditions, like hammertoes, can also contribute to the development of corns due to crooked toes constantly scraping against shoes.
There are a variety of treatments for corns, from simple at-home solutions to more serious surgical procedures. Patient satisfaction is typically high. When corns become extremely painful, foot and ankle surgeons can offer the best treatment solutions. However, unless the cause of the corn is addressed, it tends to come back. It’s generally best not to try and get rid of a corn yourself or use medicated pads for corns at home, as this could lead to a wound or serious infection.
For individuals suffering from peripheral neuropathies, it’s advised to avoid using plasters containing salicylic acid. This is because, if applied incorrectly, these plasters could damage normal skin. Fortunately, corns and calluses are not contagious or caused by viruses. One way to prevent them from forming is to keep your nails trimmed and wear shoes with more room, in order to avoid any recurring trauma or pressure that could lead to corns.
