Rheumatoid Arthritis vs Psoriatic Arthritis: What It Means for Your Joints

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Rheumatoid arthritis and psoriatic arthritis are both autoimmune diseases that cause inflammation of the joints. Although there is a huge amount of overlap between these two conditions, it is important to understand what makes them different from each other. Arthritis is simply defined as pain, swelling and or tenderness in one or more joints in the body. This condition very common and widespread. It is found in people of all ages, race and gender even though some specific types may be more common as we grow older.

Our body is protected by a series proteins, cells and organs collectively called the immune system. This system works together to protect us from outside factors such as germs, diseases and harmful chemicals. For some unknown reasons, this system sometimes turns around and starts to fight our own body cells and organs instead of protecting them from outside factors. In contrast to osteoarthritis, due to wear and tear of joint cartilages, rheumatoid arthritis and psoriatic arthritis are examples of these autoimmune diseases.

The main similarities between Rheumatoid arthritis and Psoriatic arthritis are that they are both autoimmune disorders, they both affect the joints, cause chronic fatigue or even extend to inflammation of other major organs such as heart, lungs, eyes. In both rheumatic and psoriatic arthritis, there are periods where the condition appears to disappear (called a remission) and periods where the symptoms are very active and disturbing (called a flare).

So how does rheumatoid arthritis differ from psoriatic arthritis? Rheumatoid arthritis affects the whole body symmetrically, i.e., it occurs on both sides of the body causing pain, stiffness, tiredness as well as complete destruction of body joints where our bones meet. Its affects women three times more than men and frequently starts between the ages of 40 and 60 years of age.

Psoriatic arthritis, on the other hand, occurs in 3 out of 10 people that have a degenerative immune condition called psoriasis, a disease that causes patches of skin to thicken, became scaly and or with silvery patches. For majority of people, the skin condition precedes the joint breakdown but for some, there is no order of appearance which makes diagnosis much more difficult. Joint pain, stiffness and swelling are the main signs and symptoms of psoriatic arthritis. They can affect any part of the body and can range from relatively mild to severe.

Early and aggressive treatment helps to reduce the effect of the disease on the quality of life. The goals of therapy include:

• Relieving pain

• Keeping joints as mobile as possible

• Halting disease progression

• Reducing inflammation

TREATMENT OPTIONS

After diagnosis, medications called “disease modifying antirheumatic drugs (DMARDS)” are mainly prescribed. They are available as oral medications, can be self-injected or given as an infusion in the doctor's office. Corticosteroids such as prednisone and cortisone are used as bridge therapy while pain medications like Tylenol, diclofenac (oral and topical) and Advil may also provide temporary relief.

There are 3 types of DMARDS: traditional DMARD, biologic DMARD and targeted synthetic DMARD. The treatment of rheumatoid and psoriatic arthritis is usually similar, except for in the case of newer synthetic DMARDS such as Apremilast, which is limited to the treatment of Psoriatic arthritis.

Without any contraindications, the drug of choice is a traditional DMARD called methotrexate due to its great impact on joint damage. It is available as an oral formulation and can also be self-injected. Leflunomide is another option that can be used with methotrexate or alone. Its adverse effect of diarrhea however limits its use. Efficacy of these group of drugs could take up to three months to become evident. Other traditional DMARDs include sulfasalazine and hydroxychloroquine. Their evidence is limited compared to methotrexate and are only recommended for mild disease with good prognosis. They have less impact on joint damage compared to other traditional DMARDs.

The biologic DMARDS directly attack the substances that cause bone and cartilage destruction. They reduce signs and symptoms of the disease as well as further deterioration of the joints. Unlike the traditional DMARDs, they work more quickly. They are either self-injected or administered by infusion at the doctor's office. Infliximab, adalimumab, certolizumab, etanercept and golimumab can also be used as first line options but are more effective when used with methotrexate. They have long term safety data and are very effective.

Tocilizumab and Sarilumab are effective when used alone even though combination with methotrexate is preferred. Their marked side effects such as liver injury and increased risk of perforations limits their use. Abatacept helps to reduce immune response and is effective in patients with an inadequate response to other first line therapy. Rituximab helps to regulate the immune system. It is used with methotrexate to improve outcome especially when one or more other medications have been tried.

Targeted synthetic DMARDs include Tofacitinib (Xeljanz), Baricitinib (Olumiant) and Upadacitinib (Rinvoq). They are oral medications and synthetically produced as their name denotes. They target a specific point in the immune regulation process to calm down inflammatory markers. They can be used alone or in combination with methotrexate when response from methotrexate is inadequate and or other therapies have failed. While DMARDs can be very effective, their major drawback is immune system suppression and increase in risk of infection. Apremilast (Otelza) is a unique oral synthetic DMARD which is specifically used for the treatment of psoriatic arthritis (and not rheumatoid arthritis). Apremilast works by inhibiting phosphodiesterase 4, a key component in the inflammatory responses that cause psoriasis and psoriatic arthritis.

In summary, rheumatoid arthritis and psoriatic arthritis are chronic diseases with no cure but can be managed acceptably. The joint damage they cause is progressive and lifelong treatment is mostly required. Hence early diagnosis, the right medications, physical rehabilitation coupled with a healthy lifestyle is of uttermost importance.

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