A Two Minute Review of AFP's "Psoriasis"

A brief synopsis of
Psoriasis, NANCY WEIGLE, MD, Duke University School of Medicine, Durham, North Carolina, SARAH McBANE, PharmD, University of California, San Diego, Skaggs School of Pharmacy  and Pharmaceutical Sciences, La Jolla, California
http://www.aafp.org/afp/2013/0501/p626.pdf
Am Fam Physician. 2013 May 1;87(9):626-633.

     Psoriasis is a rather common skin condition presenting as red, itchy, painful, scaly patches. There is a genetic component, but it is an immune mediated disease. It can be associated with stress, smoking, trauma, obesity, alcohol, and recent infection. The most common type is plaque psoriasis. The rash is well circumscribed and often coalesces. It is found on the extensor surfaces of the arm, legs, scalp, trunk and buttocks. Inverse psoriasis is less scaly than the plaque version. It occurs on the flexor surfaces and skinfold areas of the inguinal, intergluteal, axillary and perineal area. Erythrodermic psoriasis is accompanied by systemic symptoms, widespread edema and plaques. A localized pustular psoriasis forms on the palms and soles. It can be acute and life threatening. Guttate psoriasis presents as fine scaling and small pink papules located on the trunk. It is seen in young patients and those with a recent staph URIs.
     Nondermatologic manifestations are also prevalent. The majority of patients will also have psoriatic onychodystrophy, a nail disease. This will present as pitting, separation from the nail bed, and hyperkeratosis. It is very resistant to treatment. Psoriatic arthritis is also common. It is a seronegative inflammatory syndrome that presents about 12 years after the onset of the skin manifestations. OH, yeah, it affects the joints.
     Patients with psoriasis have an increased risk of other illnesses. There is a psychologic component,  causing social isolation, depression, and an overall feeling of unattractiveness. Patients often feel like the physician has neglected them. There is also an increased risk of crohn's, UC, squamous cell carcinoma,  lymphoma, metabolic syndrome, obesity, and heart attack.
     Treatment can be divided between disease severity. Mild/moderate disease covers less than 5% of the total body surface. It does not affect the hands, feet, face, or genitals. Treatment includes topical preparations of corticosteroids, vitamin D analogs, tazarotene, and calcineurin inhibitors (tacrolimus and pimecrolimus).  Steroids can have adverse and systemic side effects such as skin atrophy, irritation, and impaired wound healing. The symptoms will return once the corticosteroids are discontinued. Calcipotriene and calcitriol (vitamin D analogs) take longer to kick in, but the effects last longer. They  may cause hypercalcemia and parathyroid hormone suppression. Tazarotene is a topical retinoid that is similar in effectiveness to steroids, with a longer lasting benefit. Tacrolimus is better than pimecrolimus.
     Severe psoriasis presents with involvement of more than 5% total body surface area. It may affect the hands feet, face or genitals. It can be treated with phototherapy and methotrexate, cyclosporine, or acitretin. "Second tier medications" include azathioprine, hydroxyurea, sulfasalazine, leflunomide, tacrolimus and thioguanine. Methotrexate should be taken with folic acid to reduce side effects. Cyclosporine has many drug interactions, but can be used as a bridge therapy due to its rapid onset. Acitretin is a retinoid that takes about 3-6 months to be effective. Because is is teratogenic, it may cause hyperlipidemia, mucocutaneous lesions, or live damage. 
     Newer biological therapy is effective in severe psoriasis. Thery are different TNF inhibitors, such as adalimumab, etanercept, and infliximab. Infliximab has the most rapid clinical response. Etanercept is often given with methotrexate. With biologic agents, it is important ti watch for serious infecions, such as TB. They could also result in lupus like syndromes, liver issues, demylenating disorders, or heart failure axacerbation.