Overview:

• Psoriasis is a chronic proliferative and inflammatory condition of the skin. It is characterized by erythematous plaques covered with silvery scales, particularly over the extensor surfaces, scalp, and lumbosacral region.

• The disorder can also affect the joints and eyes. Psoriasis has no cure and the disease waxes and wanes with flare ups. Many patients with psoriasis develop depression as the quality of life is poor.

• There are several subtypes of psoriasis but the plaque type is the most common and presents on the trunk, extremities, and scalp. Close examination of the plaques usually reveals white silvery scales.

• The eye is involved in about 10% of patients, mostly women. In general, the eye is rarely involved alone; it is almost always associated with skin features.

Etiology

• Psoriasis has a prevalence ranging from 0.2% to 4.8%.

• The exact etiology is unknown, but it is considered to be an autoimmune disease mediated by T lymphocytes. There is an association of HLA antigens seen in many psoriatic patients, particularly in various racial and ethnic groups. Familial occurrence suggests its genetic predisposition.

• Injury in the form of mechanical, chemical, and radiational trauma induces lesions of psoriasis. Certain drugs like chloroquine, lithium, beta-blockers, steroids, and NSAIDs can worsen psoriasis. Generally, summer improves psoriasis while winter aggravates it. Apart from the above factors infections, psychological stress, alcohol, smoking, obesity, and hypocalcemia are other triggering factors for psoriasis.

Common reported symptoms

• Rashes, dryness, fissures, flakiness.

• Peeling, small bump, and thickness.

• Scalp, elbows, knees, and lower back.

• Upper and Lower extremities.

Pharmacology treatments if recommended. 

Topical treatment

• Emollient to maintain skin hydration.

• Mild to moderate potency steroids to reduce inflammation.

• Tazarotene topical cream, slowing skin cell overgrowth.

Recommend Ancillary therapies

• Discourage scratching.

• Benadryl at bed time for itching

Evaluation

• Usually, diagnosis is made by clinical morphology and site of lesions. Histopathology is rarely necessary but may help to differentiate psoriasis from another dermatosis if the diagnosis is not easy.

• Characteristic changes in biopsy show parakeratosis, micro-abscess, the absence of granular lesions, regular elongation of ridges in the form of camel foot appearance, and spongiform pustules of Kogoj with dilated and tortuous capillaries in the dermal papilla.

Laboratory studies

• One should order complete CBC, renal, and liver function tests

• Rheumatoid factor

• ESR may be elevated in erythrodermic and pustular psoriasis

• Uric acid levels are high in psoriasis

• If only hand and feet are involved, obtain scrapings for fungal studies

• Pregnancy test

• Hepatitis serology. PPD

Treatment / Management

• Psoriasis Area Severity Index (PASI) is the most widely used measurement tool which assesses the severity of the condition and allows for the evaluation of treatment efficiency.

• Topical therapy is used in mild to moderate psoriasis. Emollients and moisturizers may help in improving barrier function and retain the hydration of the stratum corneum. Topical agents used are coal tar, dithranol, corticosteroids, vitamin D analog, and retinoids are used initially. 

• In patients who do not respond to the above treatments, methotrexate can be effective.

• Cyclosporine can be used to induce a clinical response but its use should be intermittent.

• When patients fail to respond to methotrexate, switch to biological agents; in some cases combine with methotrexate (*TIME TO SEE DERM OR YOUR PCP)

• Phototherapy includes PUVA therapy which combines psoralen with exposure to ultraviolet light (UVA), as well as NBUVB (Narrowband UVB light) with a range of 311 nanometers to 313 nanometers.

• NBUVB  is equally effective without the side effects of psoralen like gastrointestinal upset, cataract formation, and carcinogenic effects.

• It can safely be given to children, pregnant and lactating females, and even older patients. Guttate psoriasis has been known to respond best to phototherapy

• Systemic drugs are used in extensive cases, the involvement of nails and psoriatic arthritis. *Methotrexate, retinoids, cyclosporine, and fumarates are possible options. Routine blood, liver functions, and renal functions should be monitored in patients on systemic therapy.

• Biologicals are manufactured proteins that interrupt the immune process in psoriasis which are infliximab, adalimumab, etanercept, and interleukin antagonists. Before starting any biological agent, the patient should be worked up for tuberculosis and hepatitis. 

• There is a serious risk of infections in these patients and all precautions should be taken that the patient is not severely immunocompromised.

• Prolonged use of steroids and other immunosuppressives may delay wound healing.

• Ocular psoriasis requires aggressive treatment with topical corticosteroids.

• Patients with psoriasis should avoid all skin trauma for fear of inducing the Kobner reaction.

• In addition, psoriatic patients should avoid the use of beta-blockers, chloroquine, or NSAIDs. They should also avoid alcohol because of the risk of developing fatty liver.

Retrieved from:

https://www.ncbi.nlm.nih.gov/books/NBK448194/

https://www.psoriasis.org/psoriasis-guidelines/

https://dermnetnz.org/topics/guidelines-for-the-treatment-of-psoriasis