What Is the Main Cause of Psoriasis?

Psoriasis is a faulty immune response that causes your body to attack its own skin and sometimes joints. The exact cause is unclear, but family history seems to play a role, as does the stress response to infection, medication side effects or prolonged emotional stress.

Psoriasis is a chronic autoimmune skin condition that causes skin to be red, thick, scaly, and flaky.

Psoriasis symptoms may worsen (flare) for a few weeks or months and then subside (go into remission). Psoriasis commonly affects the scalp, elbows, and knees. 

Symptoms of psoriasis may include:

• Patches of skin that are:
  • Thick, dry, red, or dark
  • With silvery-white scales that itch or burn
  • Dry, cracked skin that itches or bleeds
• Rashes on the:
  • Scalp
  • Genitals
  • In skin folds (armpits, groin, or under the breasts)
• Nail changes 
  • Pitted
  • Thick
  • Ridged
  • Crumbly
  • Different in color 
• Emotional effects
  • Embarrassment
  • Depression
  • Anxiety
• Psoriatic arthritis
  • Occurs in some patients
  • Stiff, swollen, painful joints

Psoriasis is caused by an overactive immune system, but the reason the immune system becomes triggered in some people is unknown. 

Risk factors that may increase the chances of developing psoriasis include:

• Family history of psoriasis
• Some types of infections, such as strep
• Certain medicines
• Smoking
• Obesity

Triggers for psoriasis flares include:

• Stress
• Skin injury, including scratches, sunburns, bug bites, and vaccinations 
• Illness, such as ear infection, bronchitis, tonsillitis, or respiratory infection
• Weather, especially cold weather 
• Allergies
• Certain foods
• Alcohol 
• Environmental factors

Psoriasis is diagnosed after taking the patient's history and a physical examination of the skin, nails, and scalp. 

In some cases, a small sample of skin may be taken to confirm a diagnosis of psoriasis.

There is no cure for psoriasis, but treatments can relieve the symptoms. Treatment for psoriasis includes: 

• Topical treatments, such as creams and ointments
  • Prescription topical treatments
    • Steroids
    • Anthralin
    • Calcipotriene (Dovonex) 
    • Calcipotriene and betamethasone (Taclonex)
    • Tazarotene (Tazorec)
    • Calcitriol (Vectical)
• Over-the-counter (OTC) topical treatments
  • Salicylic Acid
  • Coal Tar
  • Moisturizers
    • Fragrance-free
    • Apply after showering and hand washing
    • Use moisturizing soaps
• Shower in lukewarm water and limit showers to 10 minutes or less
• Bath solutions such as oil, oatmeal, Epsom salts or Dead Sea salts
• Scale lifters (keratolytics) usually contain an active ingredient of salicylic acid, lactic acid, urea, or phenol 
• Coverings (occlusion) applied over topical treatments such as plastic wrap, cellophane, waterproof dressing, cotton socks or a nylon suit
• Anti-itch treatments such as calamine, hydrocortisone, camphor, diphenhydramine hydrochloride (HCl), benzocaine, and menthol (may increase irritation and dryness)
• Aloe vera, jojoba, zinc pyrithione, capsaicin and others may also help moisturize, soothe, remove scale, or relieve itching 
• Castederm for inverse psoriasis to help dry moist plaques in the folds of the body
• Phototherapy (light therapy)
  • Ultraviolet light B (UVB): broad band and narrow band
  • Psoralen + UVA (PUVA) 
• Systemic treatments
  • Biologics and biosimilars
  • Tumor necrosis factor-alpha (TNF-alpha) inhibitors such as certolizumab pegol (Cimzia), etanercept (Enbrel), adalimumab (Humira), infliximab (Remicade), golimumab (Simponi and Simponi Aria)
  • Interleukin 12 and 23 (IL-12, IL-23) inhibitors such as ustekinumab (Stelara)
  • Interleukin 17 (IL-17) inhibitors such as secukinumab (Cosentyx), brodalumab (Siliq), and ixekizumab (Taltz)
  • T-cell inhibitors such as Orencia (abatacept)
  • Interleukin 23 (IL-23) inhibitors such as tildrakizumab-asmn (Ilumya), risankizumab-rzaa (Skyrizi), and Tremfya (guselkumab)
  • Biosimilars to adalimumab (Humira): adalimumab-atto (Amjevita), adalimumab-afzb (Abrilada), adalimumab-adbm (Cyltezo), adalimumab-bwwd (Hadlima), adalimumab-fkjp (Hulio), and adalimumab-adaz (Hyrimoz) 
  • Biosimilars to etanercept (Enbrel): etanercept-szzs (Erelzi) and etanercept-ykro (Eticovo) 
  • Biosimilars to infliximab (Remicade): infliximab-axxq (Avsola), infliximab-dyyb (Inflectra), infliximab-qbtx (Ixifi), and infliximab-abda (Renflexis) 
• Disease-modifying antirheumatic drugs (DMARDs) including tofacitinib (Xeljanz and Xeljanz XR)
• Traditional oral systemics
  • Acitretin (Soriatane)
  • Cyclosporine
  • Methotrexate
  • Off-label systemics, including hydroxyurea (Hydrea), isotretinoin, mycophenolate mofetil, sulfasalazine, and 6-Thioguanine 
• Nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin and ibuprofen (Advil, Motrin)