Only a physician can confirm whether or not you have psoriasis, so if you experience the symptoms described on the Symptoms page, make an appointment to see your doctor, who will give you a physical examination and possibly take a biopsy of the affected skin.
If you have mild psoriasis, you may be able to manage your condition without prescription-strength medication by avoiding things that you know trigger your psoriasis (e.g., stress), bathing regularly, applying moisturizer and exposing your skin to small amounts of sunlight.
However, if your psoriasis is more aggressive, there are several over-the-counter and prescription medications that can help relieve your symptoms.
These medications aim to bring your psoriasis under rapid control, reduce the body surface area it affects, clear your lesions, help to maintain clear skin and avoid a relapse, and improve your quality of life.
They include topical medications that you apply to your skin directly, phototherapy, and systemic medications that you either take orally in a pill, or by injection or infusion. 
Below is a brief overview of the different types of treatment most commonly used for psoriasis. Discuss with your doctor which treatment is right for you and what the benefits and side effects may be. Your doctor may suggest one medication, prescribe a combination, rotate between different medications, or use medications in a specific order to clear your skin. After trying one option, don’t hesitate to discuss a different treatment plan with your doctor if the approach you are currently taking is not working for you.
To get the most out of your therapy, always use your medications as directed by your doctor.

Topical Medications

About 80% to 90% of people have mild to moderate psoriasis, and most can be treated with topical agents—treatments applied on the skin—including creams, gels, ointments, solutions, foams, tapes, sprays, oils, shampoos and lotions. Topical agents may be used alone or in combination with other therapies, such as phototherapy, or systemic medications.
Topical corticosteroids
Corticosteroids are synthetic versions of hormones made in the body and are the most commonly prescribed medications for psoriasis. Corticosteroid creams, lotions, foams, gels, ointments and sprays are the most commonly prescribed topical agents for mild to moderate psoriasis. When applied to the skin, they reduce inflammation in the area, making them useful treatments for many forms of psoriasis. They are available in low-dose, high-dose and very-high-dose preparations.
Corticosteroids usually work quickly, and the low-dose formulations can be applied almost anywhere on the body. For mild psoriasis limited to a few small plaques, low-dose, non-prescription strength may be all that’s needed. However, if the plaques’ crusts are thick or if they’re widespread, high-dose topical steroids may be prescribed alone or in combination with other treatments.
Potential Side Effects
If corticosteroids are used for an extended period over a large area, it’s possible for some of the drug to be absorbed into the body. This is called systemic absorption and it can lead to Cushing’s syndrome, cataracts, glaucoma and osteoporosis. It is important to follow any instructions your doctor gives you about using a corticosteroid cream or lotion. Side effects include:
  • Fragile, thin skin, easy bruising
  • Appearance of small blood vessels
  • Bands of thin, red skin that turn into slivery lines (stretch marks)
  • Infection of hair follicles
  • Tiny red or purple spots
  • Contact dermatitis (rash)
  • Vulnerability to infections
  • Hair growth
Topical corticosteroids can worsen rosacea, around-the-mouth rashes, athlete’s foot and similar infections. Higher-potency products are usually limited in use to only two to four weeks at one time to limit the risks of systemic absorption and other side effects. After psoriasis goes away, topical corticosteroids are gradually reduced then stopped to reduce the risk of rebound outbreaks. There is some controversy over whether people can develop a resistance to topical corticosteroids over time.

Vitamin D3 derivatives

Vitamin D3 derivatives, such as calcipotriol, are available as creams, ointments and solutions typically for the treatment of mild to moderate psoriasis.
Vitamin D3 derivatives are corticosteroid-sparing – they enable you to use less topical corticosteroid. They are usually applied once or twice daily for about 8 weeks. When combined with topical corticosteroids, they can often work better in people with plaque psoriasis than either medication alone.
Potential Side Effects
Potential side effects include burning, itchiness, swelling, peeling, dryness and rash. They should not be used on the face. In patients who spread larger doses over much of their body, vitamin D3 derivatives may cause a rise in blood calcium levels, which reverses when the medication is stopped. They may also cause light sensitivity and may cause a burning sensation if applied before UVB phototherapy.
Calcitriol ointment, an active form of vitamin D, is also presently available.

Combination topical treatment

 Currently there is one combination topical treatment available forpsoriasis patients in Canada. It  contains calcipotriol (a vitamin D analogue) and betamethasone dipropionate (a corticosteroid).
Because it is a measured combination of calcipotriol and betamethasone, it has been shown to be more effective for the treatment of psoriasis and is faster acting than if the two ingredients are used alone. Even if you apply both ingredients separately but at the same time, it is hard to get the optimal proportions. Both ingredients work together to control psoriasis, and reduce the time you spend applying medication.
This ointment or gel is applied once daily, directly to the psoriasis plaques. After psoriasis has improved, application can be stopped, and restarted as needed.

Potential Side Effects

The most common side effect is mild itching and those side effects associated with the individual ingredients listed above.

Topical retinoids

Topical retinoids may be an effective treatment for mild to moderate psoriasis. At least one topical retinoid, tazarotene, is available in Canada. When combined with topical corticosteroids, tazarotene can help prevent thinning of the skin, which is a common side effect of corticosteroids.
Combining a topical retinoid with UVB phototherapy may enhance benefits and reduce the amount of UV exposure needed for a good response.
Potential Side Effects
A common side effect is skin irritation in or around plaques, which may be lessened by using a moisturizer, applying the product on alternate days, short-contact (30- to 60-minute) treatments or combining this product with a topical corticosteroid.
Pregnant and nursing women cannot take topical retinoids due to the high risk of birth defects.
Other topical agents
Over-the-counter moisturizers (emollients) leave a film on the skin’s surface, forming a barrier to retain moisture in the skin’s upper layers. These products may be soothing and may help remove the scales that form in psoriatic plaques. They may also increase the effectiveness of other topical treatments. Using a moisturizer up to three times daily is add-on therapy for psoriasis—it will not control flares on its own.
Salicylic acid can reduce scaling and soften the reddish patches (plaques) of psoriasis. It is often combined with other topical agents. It should not be applied to more than 20% of body area. It is not recommended for use in children or people with liver or kidney problems. This agent can reduce the effectiveness of UVB phototherapy and it can interact with certain oral medications.
Anthralin is a yellowish cream that is mostly used as short-contact (20- to 30-minute) therapy for mild to moderate psoriasis and hard-to-treat scalp psoriasis. Its inconvenience and poor cosmetic appearance are major downfalls. It is not as effective as prescribed topical corticosteroids or vitamin D derivatives. Anthralin can stain the skin, clothing and other objects that are touched. Other side effects include skin irritation. It is no longer commercially available but can be compounded by pharmacists.
Coal tar preparations are not used as often as they once were to treat psoriasis. Today, they are available mostly as over-the-counter shampoos and gels for mild to moderate psoriasis. Formulations are not standardized, and the effectiveness of coal tar differs from one preparation to the next. For example, some studies have found that 1% lotion works better than 5% coal extract. Odour, staining and cosmetic issues can discourage many patients from using coal tar. Potential side effects include photosensitivity to UVA light, contact dermatitis and infection of hair follicles.


Phototherapy is the use of ultraviolet light (UV) as a form of treatment. Several different forms of light treatment for psoriasis are available, including exposure to natural sunlight when conditions permit.
The goal of phototherapy is to expose the patient’s affected skin to UV light. Treatments are available at doctors’ offices, phototherapy clinics or even at home. It is used to treat moderate to severe psoriasis with plaques covering more than 3% of the skin. The most common types of UV light “wavebands” made by phototherapy medical devices are:
  • UVB-Narrowband (by far the most common, especially for home use)
  • UVB-Broadband (the original UVB waveband, used for over 50 years)
  • UVA (for the most severe cases, and always used in conjunction with a photosensitizing drug called psoralen; a treatment called PUVA)
Both UVA and UVB rays are present in natural sunlight, but the amounts vary greatly by the distance from the earth’s equator, time of year (in the earth’s northern hemisphere the maximum is on June 21 and the minimum on December 21), time of day (maximum is at high-noon), altitude, and environmental factors such as cloud cover. These variables make the use of natural sunlight difficult to administer for all but the most dedicated psoriasis patients and for Canadians at best only in the summer. If using natural sunlight, please discuss this with your dermatologist. Most importantly: NEVER GET BURNED!
Some psoriasis patients report results from the use of cosmetic tanning machines, but these machines emit mostly UVA light (which causes tanning but by itself is not effective for psoriasis), and just a small amount of the desired therapeutic UVB (up to a government regulated maximum of approximately 5%). Dermatologists strongly recommend against this practice. For psoriasis, the large amount of UVA energy is not necessary, almost certainly harmful, and best avoided by instead using a medical device that creates UVB only.
For ALL forms of UV phototherapy, it is important to note that:
  • It is probably NOT suitable for individuals with a light sensitive disease, an allergy to the sun, skin cancer; and those taking photosensitizing medications.
  • Repeated exposure to UV may cause premature aging of the skin and skin cancer, so you should get your skin examined annually for any negative effects; a “skin check”.
  • You should NEVER GET BURNED, as that may exacerbate the primary disease and greatly increase the risk of skin cancer and premature aging of the skin.
  • Many medications (taken orally, by needle or topically), cosmetics and herbal remedies can increase the skin’s sensitivity to ultraviolet radiation. If you are using any such products, consult your physician before using UV phototherapy.
  • The eyes should be protected from ultraviolet light by wearing UV-blocking goggles or sunglasses. UV can permanently damage the eyes!
  • Skin that is unaffected by psoriasis can be protected from UV exposure by using sunscreen or an opaque material (such as clothing) to block the light
  • For maximum effectiveness, UV rays must penetrate deep into the psoriasis lesion. Since dead skin partially blocks UV, results can be improved by bathing before phototherapy to soften the dead skin so it can be very gently rubbed away.
  • There is a latency period of 3 to 24 hours before maximum reddening of the skin, so UV treatments should not be repeated within twenty-four hours. Speak to your doctor about an optimal treatment plan

UVB-Narrowband and UVB-Broadband Phototherapy

UVB phototherapy is safe and effective and can be administered by a phototherapy clinic or at home. When UVB rays penetrate the skin, it slows the rapid growth of skin cells that create psoriasis lesions. Treatment protocols call for the skin to be exposed to a UVB light source for an increasing amount of time over several weeks or months. Narrowband UVB is considered more effective than Broadband UVB as it clears the skin faster, gives longer periods between outbreaks, and has less skin burning potential. From 20 to 40 treatments, two to three times weekly, are usually needed depending on severity. Once psoriasis clears, treatment usually ends until plaques begin to reappear, but continuing UVB phototherapy for eight treatments per month may prolong the time between outbreaks. Many patients can maintain clear skin for years by finding a balance between UVB treatment frequency (number of treatments per week) and treatment time (dose). UVB phototherapy is safe to use during pregnancy. UVB phototherapy can be combined with topical medications such as steroids for better results.
Recent studies show that phototherapy also treats the increased risks that psoriasis patients have for other comorbid diseases like diabetes and heart disease. This may be owing to the large amounts of Vitamin D created in the skin by UVB light.
If you purchase or rent a home phototherapy unit for convenience, be sure to discuss this with your doctor (even though a prescription is not required in Canada). Some insurance plans cover home units while others don’t. In Canada, home units are an allowable "Medical Expense Tax Credit" (METC), per the Income Tax Act, 118.2(2)(i) "phototherapy equipment for the treatment of psoriasis and other skin disorders".

Psoralen Ultraviolet-A Light Therapy (PUVA)

Psoralen is a light-sensitizing medication that enhances the effects of ultraviolet A (UVA) rays on psoriasis, hence the name PUVA. Like UVB phototherapy, PUVA slows the rapid growth of skin cells that create psoriasis lesions. Psoralen can be taken orally or applied to the skin topically, for example by taking a PUVA “bath” just before treatment. Once high levels of psoralen are present in the skin, psoriasis is exposed to UVA light under medical supervision.
PUVA can clear plaques in about 85% of people with moderate to severe psoriasis—and remission may last from a few months to longer than a year. It is slightly more effective than UVB phototherapy but has more risks and side effects, which is why UVB phototherapy is almost always tried first. Also the cost and time required to administer this treatment is higher and so its use worldwide and in Canadais in decline.
An average of 25 PUVA treatments are needed before psoriasis clears. Due to the use of psoralen, PUVA treatments are almost always administered in a clinical setting. Severe psoriasis may take longer. One or two follow-up treatments per month may help to prevent outbreaks.

Potential Side Effects - PUVA

Oral psoralen may cause nausea, vomiting, headaches and sensitivity to UV light. Topical applications can concentrate higher levels of psoralen on tough-to-treat plaques.
Certain long-term risks are associated with PUVA, particularly skin cancer, freckling and premature aging of the skin. And because psoralen stays in the eye for up to 24 hours after it is swallowed, eyes must be protected from sunlight by UV-blocking sunglasses—even indoors—to prevent cataracts.

Systemic Treatments

Systemic treatments are any form of therapy that is delivered orally (in tablet or liquid form) or through injection or intravenous infusion (drip), that work within the body  as opposed to topical treatments, which are applied directly to the skin.


Cyclosporine is a prescription drug that suppresses immune responses. It has long been considered one of the most effective treatments for psoriasis for some people. Doctors usually prescribe cyclosporine for patients with severe flares or when psoriasis rebounds after other treatments. It often clears the skin rapidly.
Potential Side Effects
Long-term use of cyclosporine carries a risk of kidney, liver and other problems, such as lymph-node cancer, increased blood pressure, and skin cancer. For this reason, cyclosporine is usually limited to short courses and is not usually taken for longer than one year, or two, at most. This medication interacts with numerous drugs, so it is important to tell your doctor about other medications and supplements that you take.
Other potential side effects include hypertension, hair overgrowth, headache, higher risk of infection, muscle/bone aches and pains, tremor, tiredness, cough, runny nose, shortness of breath, stomach pain, nausea, vomiting, diarrhea, numbness or tingling in the skin, loss of strength and more. Routine blood tests are prescribed to monitor metabolic problems such as too much magnesium or uric acid in the blood.


This drug has treated moderate to severe psoriasis for more than 50 years. Methotrexate works by suppressing the immune system—stopping the body from attacking itself—in ways that prevent skin inflammation that leads to psoriasis. It  can be very effective and some patients respond very well and take it for many years.
 Potential Side Effects
Although effective in many patients, methotrexate may carry a higher risk of infection because it suppresses the immune system.
Common potential side effects include nausea, anorexia, mouth ulcers and tiredness.  More seriouspotentialside effects include liver, kidney, lung, and bone-marrow problems. Many experts recommend that people take folate supplements while on this medication to avoid gastrointestinal and bone-marrow problems.
This medication is not for everyone; doctors do not prescribe it to pregnant or nursing women or people with liver or kidney problems, hepatitis, leukemia, or a history of not taking their drugs or alcoholism. People who take methotrexate must have periodic blood tests to check for liver problems and other side effects.
Drug interactions with the following medications should be considered:
  • Common NSAIDs, such as ibuprofen, salicylates, naproxen, indomethacin and phenylbutazone
  • Common antibiotics, including penicillins, sulfonamides, trimethoprim/ sulfamethoxazole, minocycline and ciprofloxacin
  • Thiazide diuretics, sulfonylureas, phenytoin, barbiturates, furosemide.


Oral retinoids, such as acitretin, are derived from vitamin A. They are usually reserved for the treatment of severe psoriasis that covers more than 10% of the body or causes physical, occupational or psychological disability. They are particularly helpful for palm and sole psoriasis. Oral retinoids are often combined with UVB or PUVA phototherapy and biologic therapy for greater benefits.
These medications work by slowing the growth of skin cells, preventing skin from swelling and interrupting the body’s attack on itself. When combined with other agents, they work synergistically, enabling the use of lower doses of each drug.
Oral retinoids are safe for long-term use and are often prescribed as maintenance therapy.
Potential Side Effects
 Potential side effects include eye, mouth or nose dryness, nosebleeds, dry skin, swollen or cracked lips, brittle nails, hair loss, nausea, stomach ache, muscle or joint pain, pins-and-needle sensations and itchy, burning, or sticky skin—
Oral retinoids must not be used in women of childbearing age unless they use a reliable form of contraception. Because the drug persists for long periods in the body, women should avoid becoming pregnant while taking acitretin and for a full three years after they have stopped taking it. Women who are nursing also should not take acitretin.
Routine blood tests are used to monitor cholesterol and triglyceride levels as well as liver and kidney function.
Drug interactions are possible with other psoriasis medications—such as cyclosporine—and people must avoid supplements that contain vitamin A to prevent overdose.


Biological response modifiers, more commonly referred to as biologics, are the latest entry into the therapeutic arsenal of treating psoriasis and are considered a highly effective treatment option for patients with moderate to severe psoriasis.
Biologics have up to now mainly been used by people who cannot use other treatments or whose psoriasis no longer responds with other types of therapy. 
Biologics are made from proteins that are either similar to or the same as proteins in the body’s immune system. They block interactions between certain immune-system cells that prevent the immune system from causing skin inflammation. However, this activity weakens the ability to fight infections. For that reason, before starting biologic therapy, people usually have standard vaccinations for flu, hepatitis A and B, pneumonia, tetanus, diptheria and other infectious diseases.
Before treatment begins, people generally have routine tests to detect liver problems, hepatitis and tuberculous. If you have or develop a serious infection, biologic therapy must stop until you are better.
People with congestive heart failure, multiple sclerosis (MS) or similar diseases, or MS in their family cannot take biologics. These medications should be used cautiously in people with a history or family history of cancer.
Most biologics, including adalimumab, alefacept, etanercept and ustekinumab, are given by injection just under the skin (subcutaneous injection) and can be administered by a nurse or by the patients themselves after proper training. Common side effects include mild skin reactions at the injection site, nausea, upper respiratory tract infection, rash and headache.
Another biologic, infliximab, is given by intravenous infusion or “drip” at a day clinic or hospital rheumatology department under medical supervision. Infusions of infliximab are given at two weeks, then six weeks after the first infusion, then every eight weeks. Each infusion takes about two hours, with an observation period of about one hour or more afterward. Common side effects can include fever, rash, headache, and muscle or joint pain.
How they work
Five biologic response modifiers (biologics) are used to treat moderate to severe psoriasis in Canada. They are generally divided into three groups on the basis of how they work:
  • TNF inhibitors
  • Interleukin inhibitors
  • T-cell inhibitors
TNF inhibitors Some biologics, such as adalimumab, etanercept and infliximab, block the action of tumour necrosis factor (TNF) made by the immune system. Some people with psoriasis have too much TNF in their bodies, and this overabundance of TNF can cause skin inflammation. TNF blockers can reduce the amount of TNF in the body to normal levels.
TNF inhibitors, which affect the immune system, may affect your ability to fight off infections. Be sure to tell your doctor if you have any sign of an infection or if you have a history of tuberculosis (TB) or hepatitis B. Also let your doctor know if you have infections that keep coming back or if you have a condition like diabetes, which might increase your risk of infections. If you are pregnant or nursing, you should discuss with your doctor whether to stop taking your medication temporarily.
Common side effects:
  • Adalimumab: pain, inflammation, bleeding or swelling at the site of injection. You may also experience upper respiratory tract infections, headache, rash, nausea, abdominal pains or urinary tract infection.
  • Etanercept: a mild reaction involving pain, inflammation, bleeding or swelling at the site of injection, infections and upper respiratory tract infections.
  • Infliximab: Infections, fatigue, joint pain, abdominal pain or back pain. You may also experience shortness of breath, hives or headache following an infusion.
Anti-TNFs have been widely used in other indications such as rheumatoid arthritis or psoriatic arthritis and so have demonstrated longer history with a predictable side effect profile.

Interleukin inhibitors

Interleukin inhibitors, such as ustekinumab, can prevent specific proteins in the body—called interleukins—from causing the body’s immune system to attack the skin and nails.
Common side effects
Interleukin inhibitors may affect your ability to fight off infections. Tell your doctor if you have any sign of an infection or if you have a history of tuberculosis (TB) or hepatitis B.. If you require a live vaccine, or if you are pregnant or nursing, you should discuss with your doctor whether you need to stop taking your medication temporarily.
 Other common side effects include upper respiratory infections such as sinus infection and sore throat.

Other Treatments

Other types of treatments for psoriasis are also available, including medications approved for other conditions, new and emerging therapies, and alternative and complementary therapies.

Medications approved for other conditions

Medications officially approved for treating other conditions/diseases have been tried in psoriasis with variable success. These include calcineurin inhibitors (e.g., tacrolimus, pimecrolimus) and other immune-suppressants (e.g., hydroxyurea, azathioprine, daclizumab, paclitaxel).

New and emerging therapies

Many new therapies for psoriasis have been developed recently, continually increasing the number of options for psoriasis patients. New medications and new approaches to treatment will continue to evolve over the coming years. Future research will help optimize different treatment combinations to help in situations where one therapy doesn’t work. With ever-expanding understanding of genetics, individually tailored therapies may even become common. Talk to your doctor about treatment options.

Alternative and complementary therapies

Up to 36% of U.S. adults have stated that they use some form of complementary or alternative medicine to treat their medical problems. Talk to your doctor about complementary therapies that may be right for you. Here is a brief overview of some of the most common:

Healthy diet

Many scientific studies have shown that a balanced, low-fat diet can improve your health and prevent many serious illnesses. Some doctors report that weight loss helps to improve their patients’ psoriasis, while weight gain triggers flares. Some people have found that certain foods trigger an outbreak. Eliminating these foods from their diet helps them to manage their psoriasis. However, reducing your intake of these foods will not necessarily help your psoriasis. These foods include:
  • Caffeine
  • Products that contain gluten, e.g., wheat flour
  • Alcohol
  • Sugar
Healthy eating can also improve your general well-being. Some experts believe that psoriasis may cause nutritional deficiencies in protein, folates (related to medication), water and calories. Correcting these deficiencies—if you have them—may help to improve your overall health.


Eastern cultures have practised this form of holistic medicine for more than 2000 years. An acupuncturist inserts thin needles into specific body locations to balance life energy (Qi) and allow it to flow naturally throughout the body. Most people report that the procedure is relaxing and causes minimal discomfort. The number and length of acupuncture treatments vary from one patient to another, but multiple treatments over weeks or months are most common.
There is no scientific evidence to recommend the use of acupuncture for psoriasis, and its effectiveness has not been proven in clinical studies. People with psoriasis report mixed results—some say it helps; others report no benefit.
If you go this route, choose your practitioner carefully. Look for a trained, certified acupuncturist at the Acupuncture Foundation of Canada. Make sure that only sterile, single-use needles are used to avoid the risk of transmittable infectious diseases, such as hepatitis or HIV.

Herbal supplements

Herbal supplements of any kind can change how medications work. Before taking supplements, check with your doctor and do not exceed the doses that are recommended on the product’s label. No herbal supplement can cure psoriasis, but there is some solid scientific evidence that favours the use of some supplements over others.
• Milk thistle
Milk thistle may interfere with T-cell activation in the immune system. Overactive T cells are thought to cause psoriasis. There are no studies of its effectiveness in people with psoriasis, so no one knows if this herbal supplement will really work or how much of it to take. People who take antipsychotic medication or male hormones should not take milk thistle. This supplement may cause side effects and interfere with certain medications. Talk to your doctor before using it.
• Evening primrose oil
Two studies in patients with psoriatic arthritis have shown that oral supplements and topical oils that contain evening primrose have no beneficial effects on psoriasis. This supplement may cause side effects and interfere with certain medications. Pregnant women should not take evening primrose oil.
Aloe vera
• May reduce redness, scaling, itching and swelling
• Cream must be applied several times daily for at least one or more months before skin improves
Fish oil
• Omega-3 fatty acids from 3 g or less of fish oil supplements daily may improve psoriasis
Zinc pyrithione
• Available as a spray, soap or solution for small patches of psoriasis and scalp psoriasis
• May reduce itching, redness, flaking, and scaling
• In some people, it may eliminate psoriasis scales and sores
• Tea tree oil
First used for surgery and dentistry in the 1920s, tea tree oil is an extract of the Australia tea tree (Melaleuca alternifolia). With antibacterial and antiseptic properties, it was traditionally used to treat colds, headaches, toothaches, sore muscles and skin disorders. The oil is applied to the skin; it is poisonous when taken orally. There are no studies to show that it works, whether it is safe to use and how much to use to get benefits. A variety of products are available in pharmacies and other stores, including lotions, creams, soaps and shampoos. They contain various concentrations of tea tree oil, and some may irritate your skin. Some people get contact dermatitis from tea tree oil.
• Vitamins
The recommended daily doses of vitamin supplements have not improved psoriasis in scientific studies. Before taking larger doses – a dangerous practice that can harm your health – consult a registered dietitian, certified nutritionist or your doctor.
• Oregano oil
Oregano has antibacterial and antifungal properties, which may help to improve infections that are commonly associated with psoriasis. Oral or topical forms are available. Oregano may cause contact allergy when applied to the skin.