Psoriasis is a long-term condition that affects up to 7.5 million people in the United States. Doctors do not fully understand what causes this skin condition, but they believe it may be due to a problem with the immune system.
In this article, we look at the symptoms, causes, and treatment of psoriasis on the feet. We also cover how people can tell the difference between psoriasis on the feet and athlete's foot and offer some lifestyle tips for reducing psoriasis flare-ups.
Symptoms of psoriasis on the feet
There are several types of psoriasis. The most common type is plaque psoriasis, which occurs in around 85 to 90 percent of people with psoriasis.
Plaque psoriasis can occur on almost any part of the body, including the feet. This type of psoriasis causes red, dry patches of skin known as plaques.
These plaques are usually covered in silvery scales and can be itchy and sore. In more severe psoriasis, plaques may also crack open and bleed.
A second type of psoriasis called palmoplantar pustulosis specifically affects the palms of the hands and the soles of the feet.
People with palmoplantar pustulosis psoriasis typically notice many tiny, pus-filled blisters on their feet, hands, or both. Despite their appearance, these blisters are not infectious or contagious.
A person's feet can also be affected by a rare type of psoriasis, which is known as erythrodermic psoriasis.
Erythrodermic psoriasis causes red, scaly patches on much of the body. This condition is often a reaction to sunburn or certain medications, such as corticosteroids.
Erythrodermic psoriasis can be very serious and requires immediate medical attention.
Image credit: Bernd Untiedt, 2003.
Causes, triggers, and risk factors
Psoriasis develops when the body replaces skin cells too fast. Doctors do not fully understand what causes this skin condition, but they believe it to be an autoimmune disease. This means that the body's immune system attacks healthy tissue, such as skin cells, by mistake.
A person's genes may play a role in the development of psoriasis, and it may run in families. People who have other autoimmune diseases are also more likely to develop psoriasis.
Many people with psoriasis find that certain things trigger or worsen their symptoms. Potential triggers can vary from person-to-person, but may include:
- a recent injury to the skin, such as a cut, insect bite, or sunburn
- emotional stress
- weather changes, especially when they cause skin dryness
- an illness or infection
- certain medications
Some people first notice psoriasis after they have experienced a trigger, so may mistake their foot symptoms for an allergic reaction or an infection, such as athlete's foot.
Psoriasis on feet vs. athlete's foot
Athlete's foot is a contagious fungal infection.
Athlete's foot is a common fungal infection that occurs on the feet. Unlike psoriasis, it is contagious.
A person can get athlete's foot from surfaces, towels, and clothes that have become infected with the fungus.
In most cases, athlete's foot requires treatment. However, a person can usually treat the infection at home with over-the-counter antifungal medications.
Psoriasis on the feet and athlete's foot can look similar. A person may need to see a doctor if they are unsure which condition they have, particularly if they have not had psoriasis before.
Some differences between athlete's foot and psoriasis include:
- Location. Though both conditions can affect any part of the foot, athlete's foot often appears between toes or under the nails. Psoriasis more typically affects the soles of the feet.
- Color. Psoriasis and athlete's foot can both look red and scaly. Psoriasis tends to change color and appearance over time and often begins as silvery scales.
- Pain. Psoriasis on the foot can feel sore and painful. Athlete's foot is mainly itchy, but frequent scratching can cause the infection to hurt.
- Nail changes. Athlete's foot can infect the area under the nails, turning them yellow and brittle. Psoriasis can cause the nails to look swollen or dented.
- Joint stiffness. Some people with psoriasis have stiff, achy joints, as well as their other symptoms.
Treatment for psoriasis on the feet
Some psoriasis treatments are available over the counter.
As yet, there is no cure for psoriasis, but there is a range of treatments that can help relieve symptoms and reduce flare-ups. The choice of treatment will often depend on the type, location, and severity of a person's psoriasis.
The three primary treatments are topical medications, light therapy, and systemic drugs.
Topical medications come in the form of creams, ointments, and oils that people apply directly to their skin. Examples include:
- emollients, which are non-cosmetic moisturizers
- vitamin D analogs
- calcineurin inhibitors
- coal tar
A person can buy some topical treatments, such as emollients, mild steroids creams, and coal tar foams, over the counter. A doctor can prescribe stronger topical formulations.
Light therapy, also known as phototherapy, usually takes place in hospitals or clinics and involves doctors exposing a person to ultraviolet light. For light therapy to be effective, people may require 2 or 3 sessions a week.
Systemic treatments work throughout the body and include oral and injected drugs. Doctors typically only prescribe these medications for severe psoriasis due to the risk of serious side effect and the need for close monitoring.
Examples of systemic treatments include:
- immunosuppressants, such as methotrexate or cyclosporine
- phosphodiesterase 4 inhibitors
Treating psoriasis on the feet can be challenging due to its location. Working with a doctor, people may need to try several different treatments before finding one that is effective. In some cases, an individual may require a combination of treatments.
A doctor may recommend coal tar, light therapy, or systemic drugs for people with psoriasis on the feet that they find difficult to treat in other ways.
Some lifestyle changes may help reduce or prevent flare-ups of psoriasis. These may include:
- Staying healthy, such as by maintaining a healthful weight, avoiding smoking, reducing alcohol intake, and eating a balanced diet.
- Keeping the skin moisturized, such as by regularly using emollients and avoiding soaps and cosmetics that can dry the skin.
- Using a symptoms diary to identify and avoid specific triggers, such as foods and weather.
- Minimizing stress, such as through meditation, yoga, therapy, or other strategies.
- Taking regular exercise.
Psoriasis on the feet can be painful and more challenging to treat than psoriasis on other parts of the body. There are many treatment options available, but a person may need to work with their doctor to find one that is effective for them.
Keeping the skin moisturized, avoiding potential triggers, and maintaining a healthful lifestyle may also help prevent psoriasis flare-ups.