By inhibiting PDE4, an enzyme which breaks down cyclic adenosine monophosphate, cAMP levels rise, resulting in the down-regulation of various pro-inflammatory factors including TNF-α, interleukin 17 and interleukin 23, as well as the up-regulation of anti-inflammatory factor interleukin 10. It is given in tablet form and taken by mouth. Side effects include headaches, back pain, nausea, diarrhea, fatigue, nasopharyngitis and upper respiratory tract infections, as well as depression and weight loss. It was patented in 2014 and manufactured by Celgene. There is no current generic equivalent available on the market. Other treatments
A review found tentative evidence of benefit of low level laser therapy and concluded that it could be considered for relief of pain and stiffness associated RA.Retinoid etretinate is effective for both arthritis and skin lesions. Photochemotherapy with methoxy psoralen and long-wave ultraviolet light (PUVA) are used for severe skin lesions. Doctors may use joint injections with corticosteroids in cases where one joint is severely affected. In psoriatic arthritis patients with severe joint damage orthopedic surgery may be implemented to correct joint destruction, usually with the use of a joint replacement. Surgery is effective for pain alleviation, correcting joint disfigurement, and reinforcing joint usefulness and strength.
Differential diagnosis
Several conditions can mimic the clinical presentation of psoriatic arthritis including rheumatoid arthritis, osteoarthritis, reactive arthritis, gouty arthritis, systemic lupus erythematosus, and inflammatory bowel disease-associated arthritis. In contrast to psoriatic arthritis, rheumatoid arthritis tends to affect the proximal joints (e.g., the metacarpophalangeal joints), involves a greater number of joints than psoriatic arthritis, and affect them symmetrically. Involvement of the spinal joints is more suggestive of psoriatic arthritis than rheumatoid arthritis. Osteoarthritis shares certain clinical features with psoriatic arthritis such as its tendency to affect multiple distal joints in an asymmetric pattern. Unlike psoriatic arthritis, osteoarthritis does not typically involve inflammation of the sacroiliac joint. Psoriatic arthritis sometimes affects only one joint and is sometimes confused for gout or pseudogout when this happens. Classification
There are five main types of psoriatic arthritis:
Oligoarticular: This type affects around 70% of patients and is generally mild. This type does not occur in the same joints on both sides of the body and usually only involves fewer than 3 joints. Polyarticular: This type accounts for around 25% of cases, and affects five or more joints on both sides of the body simultaneously. This type is most similar to rheumatoid arthritis and is disabling in around 50% of all cases. Arthritis mutilans (M07.1): Affects less than 5% of patients and is a severe, deforming and destructive arthritis. This condition can progress over months or years causing severe joint damage. Arthritis mutilans has also been called chronic absorptive arthritis, and may be seen in rheumatoid arthritis as well.