The majority of the biologic therapies involve changing the amount of Tumor Necrosis Factor - Alpha (TNF-Alpha). TNF-alpha is involved in regulating abnormal responses like inflammation, increased blood vessel formaton (angiogenesis), and excessive development of skin cells (keratinocyte proliferation). It can also affect bone and cartilage erosion hence the reason that psoriatic arthritis is especially responsive to the new biologic therapies.

High Levels of TNF-Alpha are found in psoriasis as well as a host of other conditions including Crohn's disease, juvenile rheumatoid arthritis, and ankylosing spondylitis.

Interestingly, the severity of psoriasis correlates quite well with the levels of TNF-Alpha found in the blood.

The goal of the TNF inhibitor biologic therapies is to eliminate the excess TNF that is present so that you have normal levels. It is the excess TNF that is associated with the inflammatory reactions and hence some of the diseases manifestations. All of the underlying reasons for this are still uncertain.

Early treatments in psoriasis targeted large sections of the immune system. As we learn more the therapies such as the ones discussed in this article become more and targeted and affect a smaller segment of the immune system apparatus.

The three TNF inhibitors are etanercept (Enbrel), infliximab (Remicade) , adalimumab (Humira).

The medicines at this point appear safe. They should not be used in patients with a history of tuberculosis and congestive heart failure. As a dermatologist I have seen enormous improvements in the quality of life of patients due to these medicines. Caution still needs to be exercised as these are relatively new medicines and I feel they should be prescribed only when other medicines have failed or if there are signs of early and progressive joint involvement with failure of other medicines.

If one is able to completely control psoriasis with topical medicines and moderate light exposure / ultraviolet light phototherapy then this should be continued. I do not feel at this point that one should use these medicines because of the "ease" of treatment if other low risk traditional treatments work.

Due to the cost of these medicines and the profits the drug companies have the potential to make, there is an aggressive marketing campaign to promote these drugs direct to people with psoriasis. As a result, I often have patients who come in requesting these medicines without them having any knowledge beyond 30 second commercials.

I tell all patients that at this point they appear safe with the emphasis on the "at this point." We never know what potential problems could arise 20-30 years down the road although they do appear safe. The decision to go on a biologic therapy should be balanced by several factors. 1) Do you have psoriasis covering a large part of your body and have conventional treatments that have been done exactly as prescribed by your doctor failed? 2)Do you have progressively worsening psoriatic arthritis?

If you have answered yes to either of the above questions you could be a candidate for these medicines and as always you should discuss treatment options with your physician.

Unfortunately, the medicines are not able to be taken by mouth. The simple reason for this is that biologics are proteins in structure and would be digested if taken by mouth. So, they must be given by injection or intravenously. The overwhelming majority of patients have little problem with this. The point I want to make is that just because they are injectable or intravenous does not mean that they are stronger with more side effects than medicine taken by mouth.

In summary, the new biologic therapies in psoriasis and other diseases like Crohn's and Rheumatoid Arthritis are a great advance in treatment and have improved the quality of life of many people suffering from the above diseases. They represent a whole new way of targeted treatment and are best used when safe, well known traditional treatments have failed.

About the author:

Jonathan Carp, M.D. is a board certified dermatologist practicing in Southern California. Although a firm believer and practictioner of western medicine, he has a special interest in nutrition, anti-aging medicine, fitness, and traditional health maintenance practices. He is committed to providing sensible, sound, scientfically-based health information. He publishes a psoriasis health blog at http://www.psoriasisinsider.com/