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The symptoms of psoriasis may appear similar to those of other conditions, including ringworm — a fungal infection of the skin or scalp. Both psoriasis and ringworm can present as a rash on the skin. Both can cause intense itching and result in circular patches of flaking or scaly skin. If you’ve never been diagnosed with either condition, it may be difficult to tell which one is causing these symptoms.
Psoriasis is a chronic skin condition that occurs when the immune system mistakenly attacks the skin, causing inflammation and the accelerated production of skin cells that results in patches of thick, scaly skin. Ringworm is a fungal infection, caused by common mold-like parasites living on the outer layer of skin cells.
Although the differences between psoriasis and ringworm should be clear to a doctor or dermatologist, it may help to understand the differences between the symptoms, causes, and treatments of psoriasis and ringworm.
Ringworm gets its name from its appearance: a ring-shaped rash. Characteristics include discoloration — generally red, gray, or brown, depending on skin color — and itchiness. It has clearer skin in the center, giving the rash its ring-like appearance. Close examination of the ringworm rash shows a little bit more scale on the leading edge of the ring. This ring may be raised and may expand over time, while the inside of the ring may contain scattered, discolored bumps. A person with ringworm may have several rings that overlap or exist independently of one another.
Psoriasis most often presents with dry, discolored, cracked patches of skin (plaques) that are covered with silvery, gray, or clear scales. These plaques may itch, burn, or bleed. Like the rings of a ringworm rash, psoriasis plaques may remain separate or join together to form one larger patch on the skin.
The severity and appearance of psoriasis can vary from person to person. Whereas some people might only see mild flaking in one or two areas, others may have hardened, scaly, irritated patches across much of their body. Individual psoriasis plaques can also vary in size and intensity.
The symptoms of psoriasis can also vary by what type of psoriasis a person has. Some types may cause symptoms more closely resembling a ringworm rash than others. The three types of psoriasis that may be confused with ringworm are inverse, plaque, and guttate psoriasis. As one MyPsoriasisTeam member wrote, “It looks like I have ringworm all over my mid-body.”
According to the National Psoriasis Foundation, 45 percent to 56 percent of people living with psoriasis develop the condition on their scalp. Scalp psoriasis can affect the scalp itself, as well as the hairline, forehead, back of the neck, and skin around the ears, causing raised, discolored, scaly plaques that may itch. Flaking and thick scales are common, which can look like an extreme case of dandruff.
Ringworm can also develop on the scalp. Unlike psoriasis, however, ringworm on the scalp affects both the scalp and hair shafts. Ringworm of the scalp is most common in toddlers and school-aged children. Symptoms may vary, but it usually causes itchy, scaly, bald patches on the head. The scalp may also have silvery or gray scales and patches of broken hair, as well as small black dots if the hair has broken off right at the scalp. There are usually enlarged lymph nodes associated with this fungal infection of the scalp.
Psoriasis, unlike ringworm, is often accompanied by more than just skin symptoms. Psoriasis is an autoimmune condition — meaning the body’s immune system is overactive. These symptoms tend to occur in cycles, appearing during flare-ups, then fading after a few weeks or months in periods of remission. Aside from skin plaques, many people with psoriasis also have thick, pitted, or ridged fingernails and toenails. Psoriasis may be accompanied by psoriatic arthritis, which can affect the joints, causing them to ache or feel stiff.
Finally, psoriasis can affect any area of the body, whereas ringworm is most common on the arms, legs, trunk, and buttocks. Ringworm rash also develops in a shape resembling a circle or set of circles, while psoriasis rashes can take any shape.
Just as the symptoms of psoriasis and ringworm differ, so to do their respective causes and associated risks. Understanding these can be helpful in managing symptoms — and in the case of ringworm, preventing the spread of a highly contagious disease.
Although researchers are not sure exactly what causes psoriasis, it likely develops in response to a combination of genetic and environmental factors. Psoriasis is not contagious. It does not spread from person-to-person contact.
Psoriasis is an autoimmune disease, meaning it occurs when the immune system mistakenly attacks the body’s own healthy tissues (in this case, the skin). The body responds to these attacks by producing new skin cells at a highly accelerated rate. The skin does not shed quickly enough to keep up, resulting in the thick, scaly skin patches characteristic of psoriasis.
People with psoriasis may experience periodic flare-ups throughout their lives. Several risk factors are thought to trigger or worsen psoriasis flare-ups, including:
Ringworm of the body, also known as tinea corporis, is related to the infections athlete’s foot (tinea pedis), jock itch (tinea cruris), and ringworm of the scalp (tinea capitis). Although its name may suggest otherwise, ringworm is caused by infection from a certain type of fungi known as dermatophytes. No worm is involved in the infection.
Ringworm is contagious and may spread in several different ways, including skin-to-skin contact, direct contact with an infected animal, or contact with an object that a person or animal with the infection has touched. In rare cases, ringworm may also be contracted from contact with infected soil. The spores that cause ringworm can remain contagious for up to 18 months.
If you’re experiencing skin symptoms, the best thing to do is see your dermatologist or doctor for the right diagnosis and treatment.
Psoriasis is typically diagnosed by inspecting the affected areas of the body. If a doctor suspects psoriasis, they will likely examine your skin, nails, and scalp. They may also ask you about your family history and any other symptoms you’re experiencing. In some cases, a doctor may want to confirm a diagnosis by performing a biopsy. For a biopsy, a small piece of skin is removed and examined in a lab for characteristic signs of psoriasis.
Many doctors and dermatologists can diagnose ringworm based on its appearance. The circular shape of a ringworm rash is so distinctive that you may not require further testing. However, if a doctor is unsure, they will likely take a biopsy, just like with psoriasis, to examine the affected skin under a microscope and confirm the diagnosis. A skin scraping can also be done to look for fungus under the microscope. This procedure can be done in a matter of minutes.
Ringworm can be mistaken for psoriasis if the diagnosis is made by someone who is inexperienced with the two conditions, or if the circular part of the ringworm rash has not yet developed. In some cases, psoriasis may be diagnosed after treatments for ringworm have failed to improve a person’s symptoms. Note that psoriasis can also be mistaken for eczema (atopic dermatitis) or an allergic reaction.
It is possible to have both psoriasis and ringworm at the same time. A person could experience a psoriasis trigger and exposure to a fungal infection and develop both conditions simultaneously. Having both conditions could confuse a diagnosis and make it harder for a doctor to determine which part of a scaly patch comes from psoriasis and which part from ringworm. They can occur more commonly in areas where skin folds on itself, so you can have inverse psoriasis and fungus in the same area.
As some MyPsoriasisTeam members have shared, getting the right diagnosis can be tricky. The symptoms of psoriasis and ringworm can appear very similar, even to medical professionals.
One member asked if anyone else with psoriasis had been misdiagnosed, writing, “I went to the dermatologist finally and got a Cormax (clobetasol) solution and a shampoo, but they are saying it’s not psoriasis. When I was five, I was told that it was ringworm, and then when I was 17, I was told it’s psoriasis.”
Another member shared that they had also been misdiagnosed. It wasn’t until their doctor performed a biopsy that a diagnosis of psoriasis was confirmed.
Ringworm can often be treated with over-the-counter antifungal creams. If that doesn’t help, a doctor may prescribe stronger antifungal ointments or oral antifungal medications.
Treating psoriasis can be more complex than treating ringworm. It may take some time for you and your doctor to figure out what works best for your body. In some cases, topical therapies, like corticosteroid creams or retinoids, are enough to improve the condition. Light therapy, or phototherapy, that delivers controlled doses of UVB rays can also sometimes help. Other people diagnosed with psoriasis may need injected steroids, oral or injected methotrexate (such as Otrexup or Trexall), or injected biologics to see improvement for their skin condition.
If a person is diagnosed with both ringworm and psoriasis at the same time, they should not use steroid treatments until the ringworm has been successfully eliminated. Otherwise, the steroids may suppress the body’s immune response to fight the fungal infection and cause it to grow significantly faster. Once the fungus is gone, the person can treat their psoriasis as needed.
MyPsoriasisTeam is the social network for people with psoriasis and psoriatic arthritis and their loved ones. On MyPsoriasisTeam, members regularly ask questions, share advice, and talk about daily life with psoriasis.
Have you ever received an incorrect diagnosis for your skin condition? Have you experienced ringworm? Share your story in the comments below or by starting a new conversation thread.