Psoriasis is a chronic inflammatory skin condition that can present in many ways. It can look like large silvery red plaques on the scalp, elbows, knees, or everywhere (plaque psoriasis). It can be little pustules (white liquid filled bumps) that are only on the nails (nail psoriasis; or acrodermatitis continua of Hallopeau) on the hands or feet (palmoplantar pustular psoriasis) or everywhere (pustular psoriasis). It can look like little rain drops scattered everywhere (guttate psoriasis) or only be in the folds of your skin such as armpit or groin (inverse psoriasis). The most severe form is when plaque psoriasis or pustular psoriasis is so bad it makes the entire body bright red (erythrodermic psoriasis).

What causes psoriasis?

No one knows for sure but there’s a strong genetic and environmental component. Often, psoriasis runs in families but you can be the first in your family to develop genes for psoriasis. Interestingly, one third of patients with psoriasis have family members with psoriasis. Environmental means that infections or stress can trigger psoriasis for the first time in someone. For example, someone develops strep throat infection, and all of a sudden their body breaks out in a guttate psoriasis flare. This flare can resolve on its own or it can turn into plaque type psoriasis. Genetic studies show that there are certain genes that put one at risk to getting psoriasis at an early age, later age, getting guttate psoriasis, arthritis, or nail dystrophy called HLA-C*06:02.

Is a biopsy necessary for the diagnosis of psoriasis?

Not really. Only if the diagnosis is not obvious to your dermatologist. There is a misconception that biopsies will give you slam dunk results. Meaning, if you get a skin biopsy, the answer will be revealed 100% of the time. The answer is not always, except in select cases, such as skin cancers or certain infections.

For psoriasis, it can be a slam dunk diagnosis, if the lesion biopsied presents classicallly. Or it can say that features are “suggestive of psoriasis.” This can happen sometimes when patients partially treat psoriasis with over the counter medications, sometimes changing the classic signs that dermatopathologist look underneath the microscope to yield the diagnosis. Many rashes look similarly under the microscope, so the dermatopathologist does not always give a final answer, they may hedge a little and describe the skin under the microscope, suggesting multiple diagnosis that may have a similar appearance.

What makes psoriasis worse/better?

• Infections (ie. strep throat)
• Injuries (koebner phenomenon – describes any skin injury leads to new psoriasis areas)
• Too much sun (especially sunburns)
• Obesity
• Smoking
• Alcohol
• Stress
• Pregnancy (~1/2 of patients improve and 1/2 patients get worse)
• Certain medications such as lithium, beta blockers, NSAIDs, etc.

Does psoriasis affect other organs?

Patients with psoriasis tend to have other medical conditions as well. This is believed to be due to chronic inflammation that can happen in the body. Some associated conditions include: arthritis, depression, anxiety, inflammatory bowel disease, uveitis (inflammation of the eye), celiac disease, metabolic syndrome (obesity, hypertension, hyperlipidemia, cardiovascluar disease, type 2 diabetes), nonalcoholic fatty liver disease and more.

What are some treatments for psoriasis?

Psoriasis is often characterized into mild, moderate, and severe based on body surface area affected, Psoriasis Area and Severity Index (PASI) and quality of life measures.

For mild psoriasis, topicals are often used. Some over the counter options are good moisturizers, salicylic acid, coal tar, etc. Prescriptions include topical steroids, topical calcineurin inhibitors (ie. tacrolimus, pimecrolimus), topical vitamin D (calcipotriene, calcitriol), topical vitamin A (tazarotene), or compounded medications that contain several ingredients together for easier application.

For moderate-severe psoriasis, patients may be offered light therapy (narrowband UVB), and/or systemic medications which are subcategorized into oral therapies or injectable medications. For women of child-bearing age, one has to take into account which medications have teratogenic effects, meaning risks to the unborn baby. Safer medications for women who are thinking of getting pregnant, already pregnant, or breastfeeding may include biologic medications. Studies show that certolizumab (Cimzia) has minimal transfer into the placenta or breast milk.

Oral medications for psoriasis include methotrexate, cyclosporine, acitretin, apremilast, mycophenolate mofetil, hydroxyurea, azathioprine, and 6-mercaptopurine. Biologics or injectable medications are targeted therapies against inflammatory proteins in the body known to worsen psoriasis. The list of biologics and their approval date for psoriasis include:

• Anti-tumor necrosis factor
  • Etanercept – Enbrel – 2004
  • Infliximab – Remicade – 2006
  • Adalimumab – Humira – 2008
  • Certolizumab – Cimzia – 2018
• Anti-IL12/23
  • Ustekinumab – Stelara – 2009
• Anti-IL17
  • Secukinumab – Cosentyx – 2015
  • Ixekizumab – Taltz – 2016
  • Brodalumab – Siliq – 2017
• Anti-IL23
  • Guselkumab – Tremfya – 2017
  • Tildrakizumab – Ilumya – 2018
  • Risankizumab – Skyrizi – 2019

Biologics approved for both psoriasis + psoriatic arthritis include anti-TNFs [infliximab (Remicade), adalimumab (Humira), etanercept (Enbrel), certolizumab (Cimzia)], anti-IL17 [secukinumab (Cosentyx)], anti-IL12/23 [ustekinumab (Stelara)], anti-IL23 [guselkumab (Tremfya)]. As you can see, there are so many options, and there’s subtle reasons why one is favored over another for each patient. Find a dermatologist to discuss what treatment options is best for you.