Ringworm is a fungal infection that appears as a small circular rash, usually on the arms or legs, whereas psoriasis is a chronic skin condition that causes scaly, itchy patches, often on the knees or elbows.

Psoriasis and ringworm (dermatophytosis) are sometimes compared because they can look similar, especially in early stages.

Both can cause discolored, scaly patches that may appear circular or slowly expand, making them easy to confuse.

Psoriasis is a chronic, immune-mediated condition that speeds up skin cell growth, leading to buildup on the skin’s surface. It most often appears on the knees, elbows, genitals, and toenails, and it is not contagious.

In contrast, ringworm is a temporary fungal infection that affects the outer layer of the skin. It can form ring-shaped rashes that may itch, expand over time, and spread through direct contact or contaminated surfaces.

In this article, we’ll break down the key differences in symptoms, share tips to help identify each condition, and review how they are treated.

Psoriasis and ringworm can both cause scaly, discolored patches on the skin, but they differ in how those patches look, feel, and change over time.

Symptoms of psoriasis

Your symptoms of psoriasis may differ from someone else’s, depending on the type of psoriasis and where it appears on the body.

Psoriasis symptoms may include:

  • red or pink with silvery-white scales on lighter skin tones
  • salmon-colored with silvery-white scales on medium skin tones
  • violet, gray, or dark brown on darker skin tones (may be more difficult to see)
  • small spots of scaling
  • dry, cracked skin that might bleed
  • itching or burning
  • soreness on spots
  • sore or stiff joints
  • thick, ridged, or pitted nails

Psoriasis is a chronic condition. It may cause one or two patches or clusters that grow to cover a large area.

There is currently no cure for psoriasis, but treatment can help manage symptoms and, in some cases, lead to on-treatment remission, where skin lesions clear or significantly improve.

However, psoriasis is a chronic inflammatory condition, and disease activity may persist even when visible skin symptoms are minimal or absent. For example, inflammation can persistently affect joints in people with psoriatic arthritis.

Symptoms and disease activity may also flare or improve over time, resulting in periods of increased and decreased activity.

Symptoms of ringworm

In contrast, the signs and symptoms of ringworm can change as the infection spreads.

Ringworm symptoms may include:

  • red or pink patches on light skin tones
  • brown or gray patches on medium to dark skin tones
  • a raised border around the scaly area
  • an expanding scaly area that forms a circle
  • a circle with red bumps or scales and a clear center

You may develop more than one ring-shaped patch, and these can overlap or grow together. The borders may appear uneven or irregular as the infection progresses.

While psoriasis and ringworm can look similar, a few key features can help point to one condition over the other.

Psoriasis is more likely if you have thicker patches of skin with silvery or scale-like buildup, symptoms that come and go over time, nail changes, or joint stiffness.

Ringworm is more likely if the rash is ring-shaped, has a clearer center with a raised outer edge, is spreading outward over days to weeks, or follows contact with a person, pet, or surface with a fungal infection.

When in doubt, a healthcare professional can confirm the diagnosis and recommend the appropriate treatment.

Psoriasis and ringworm require very different treatments because they have different underlying causes: Psoriasis is an immune-mediated condition, while ringworm is a fungal infection.

Treatment for psoriasis

There is currently no cure for psoriasis, but treatments can help reduce symptoms and manage flare-ups. The type of treatment depends on the severity and type of psoriasis.

Common treatment approaches include:

Topical treatments

Your doctor may prescribe a medicated cream, ointment, or another solution to treat your mild to moderate psoriasis.

These types of topical treatments include:

Light therapy

Light therapy uses controlled exposure to ultraviolet light to slow skin cell growth.

Options may include:

  • natural light (sunlight)
  • UVB light
  • photochemotherapy UVA
  • lasers

Because certain types of light exposure can worsen symptoms, phototherapy should only be used under medical guidance.

Oral or injected medications

Your doctor may prescribe oral or injectable medications if you do not respond well to other treatments. They’re appropriate for various forms of moderate to severe psoriasis.

These medications include nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and disease-modifying antirheumatic drugs (DMARDs). They can alter how the immune system functions, leading to slower skin cell growth and reduced inflammation.

DMARDs can be nonbiologics or biologics.

Nonbiologics include:

Biologics used for psoriasis or psoriatic arthritis include:

Infliximab (Remicade), golimumab (Simponi), and brodalumab (Siliq) are biologics used to treat psoriasis, but they’re less commonly used than other options.

Because these medications can have significant side effects, they are typically used when needed and may be adjusted or combined depending on response.

Treatment plans are often individualized, and healthcare professionals may use combination therapy to improve effectiveness while minimizing doses.

Treatment for ringworm

Ringworm is treated with antifungal medications that target and eliminate the fungus causing the infection. Treatment is usually straightforward, especially when started early, and most cases improve within a few weeks.

  • Over-the-counter topical antifungals: These are often the first-line treatment for mild or localized infections. Options include terbinafine (Lamisil AT), clotrimazole (Lotrimin AF), and ketoconazole.
  • Prescription-strength topical antifungals: These may be used if the infection is more widespread, persistent, or not responding to over-the-counter treatments.
  • Oral antifungal medications: These are used for more severe or widespread infections, or when the infection involves areas such as the scalp or nails.

In addition to medication, it is often recommended to keep the affected area clean and dry and to avoid sharing personal items like towels or clothing, as ringworm can spread through direct contact or contaminated surfaces.

Make an appointment with a healthcare professional if you develop an unusual rash or skin changes that do not improve or are difficult to identify.

If you think you may have been in contact with a person or animal with ringworm, let your clinician know, as this can help guide diagnosis and treatment.

If you have a family history of psoriasis, sharing that information can also be helpful. In many cases, psoriasis or ringworm can be diagnosed by physical exam of the skin, sometimes with additional testing if needed.

If you have been diagnosed with either condition, contact your healthcare professional if you notice any of the following:

  • joint pain, swelling, or stiffness
  • difficulty using your hands or joints due to pain or swelling
  • a rash that is interfering with daily activities
  • concerns about changes in your skin’s appearance
  • a rash that is worsening or not improving with treatment

Psoriasis and ringworm can sometimes look similar on the skin, but they have very different causes, timelines, and treatments.

Psoriasis is a chronic, immune-mediated condition where symptoms can come and go over time and is not contagious, while ringworm is a temporary fungal infection that spreads through direct contact and typically improves with antifungal treatment.

Although both can cause discolored, scaly patches, psoriasis is often longer-lasting and may involve other symptoms, such as nail changes or joint discomfort, whereas ringworm usually appears as expanding, ring-shaped lesions with a clearer center.

Getting the right diagnosis is important because the treatments for each condition are not interchangeable.