The Psoriasis Glossary I Wish I Had When Diagnosed

A diagnosis can feel overwhelming, full of confusing and foreign medical terms. I’ve compiled essential, simplified psoriasis definitions to empower you to learn what’s going on in your body, decipher the doc’s notes, and develop a plan for relief.

Getting diagnosed with a chronic condition can be confusing, overwhelming, and lonely. When I was informed of my plaque psoriasis diagnosis in 2021, the doctor referred me to Google to learn more, failing to even mention the little term “chronic.”

Experiences like mine aren’t uncommon, so I made it my mission to compile a psoriasis glossary to help others navigate this complex diagnosis with confidence.

Whether you’re new to the psoriasis world or want a refresher, this terminology list is a much better solution than doomscrolling!

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What’s my body up to?

Immune system: Your body’s system of defense against bacteria, viruses, and other harm.

Inflammation: The immune system’s protective response triggered by bacteria, infections, allergens, or injury. This often shows up as skin rashes, swelling, or redness and other color changes.

Autoimmune disorder: A disorder in which an overactive immune system mistakenly attacks your healthy cells and tissues.

Proliferation: An abnormal growth rate of cells. In psoriasis, we see this in skin cells!

Nail dystrophy: Abnormal changes to the shape, color, texture, or growth of nails.

Why me? Why now?

Risk factors: Personal characteristics that increase your likelihood of having a condition. Some people inherit genes that make them more likely to develop psoriasis. Others have lifestyles or make choices that increase their risk. Family history, smoking, certain medications, obesity, and hormonal changes are all known risk factors for psoriasis.

Triggers: Factors that affect when and where your symptoms appear, reappear, or worsen. While risk factors might be imagined as an unstable foundation of a house, triggers are a tornado. Both contribute to the house falling, but a trigger can be pinpointed as the catalyst or last straw. Triggers are often temporary — stress, weather, injury — but powerful enough to spark disease onset when layered with risk factors. Post-diagnosis, we also look at triggers to identify immediate causes of flare-ups. Triggers are anything that contributes to worsening symptoms.

Flare-up: Chronic conditions have symptoms that may cycle seasonally or sporadically. When symptoms reappear or worsen, it’s called a flare-up.

Skin trauma: An injury that compromises the skin’s protective barrier via force, friction, pressure, or heat. This includes cuts, burns, tattoos, insect bites, blisters, scrapes, etc.

Testing, tracking, and tallying up

Biomarker: Measurable characteristics that capture what’s going on in a body at a specific moment. Biomarkers are key indicators of health and disease, but also help doctors predict and monitor treatment responses. Common biomarkers include heart rate, body temperature, and complete blood counts.

Biopsy: A quick in-office procedure and microscopic analysis that solidifies a diagnosis. Skin biopsies involve removing a sample of surface tissue for testing in a lab.

Rheumatoid factor (RF): RF is an antibody produced by the immune system to destroy bacteria. An RF test measures its presence in your blood, with high levels being linked to autoimmune conditions. It can be used to confirm a suspected psoriasis diagnosis.

BSA: Body surface area (or total BSA). BSA assigns how much of the body is affected by your psoriasis and helps indicate severity. For psoriasis, under 3% is mild, 3% to 10% is moderate, and 10% or more is severe.

PASI: The Psoriasis Area and Severity Index is a standardized scale to assess the extent of psoriasis, primarily in clinical trial settings.

NAPSI: The Nail Psoriasis Severity Index is a standardized evaluation of psoriasis severity specifically for nails. It’s calculated by visualizing the nail in quadrants, rating psoriasis symptoms of each section, and then adding the quadrants for a cumulative NAPSI score.

Symptom awareness

Plaque: A well-defined scaly patch on the skin characteristic of psoriasis — sometimes referred to as a lesion. Plaques can be thick, raised, flat-topped, dry, and itchy. They appear silvery red on lighter skin and grayish on darker skin tones. The thickness is caused by the rapid growth of skin cells that can’t be shed quickly enough.

Extensor surfaces: Skin surfaces on the outside of a joint (e.g. elbows, knees).

Scaling: Buildup of dead skin cells caused by an abnormal growth rate.

Koebner phenomenon: When people with psoriasis injure their skin, plaques tend to emerge in the compromised location, even if previously unaffected by psoriasis. This reaction is called the Koebner phenomenon.

Onycholysis: The separation of a nail from its nail bed.

Pitting: Depressions or dents in nail surfaces.

Uveitis: Eye inflammation causing pain, redness, and blurred sight.

Psoriatic arthritis (PsA): About 1 in 3 people with psoriasis develop psoriatic arthritis. This causes chronic pain, swelling, and joint deterioration, plus general stiffness and fatigue. Both psoriasis (PsO) and PsA stem from an overactive immune response, but the arthritic component involves joint cells, too. One condition doesn’t necessarily cause the other, nor are they linked in severity. People with PsA usually see rheumatologists for joint care.

Forms of psoriasis

Psoriasis (PsO): A chronic autoimmune condition where the body creates extra inflammatory proteins. Psoriasis can take several forms, each with unique features: plaque, inverse, guttate, pustular, and erythrodermic. PsO is often referenced by the affected area, such as scalp, nail, or genital psoriasis. While there’s no cure yet, psoriasis treatments and lifestyle changes together can reduce its impact on daily life.

Plaque psoriasis: Also known as psoriasis vulgaris, plaque psoriasis is the most common form of psoriasis. It’s named for its most visible symptom, plaques prompted by excess inflammation.

Inverse psoriasis: Also called flexural psoriasis, this causes smooth patches of inflamed skin with minimal scaling. Inverse psoriasis mainly affects skin folds under the breasts, armpits, navel, groin, and buttocks. It worsens with friction and sweating.

Pustular psoriasis: A rare type of psoriasis with defined pus-filled sores, either affecting widespread or localized patches of skin. Pustules develop quickly, even just hours after inflammation, and tend to recur.

Guttate psoriasis: Also called eruptive psoriasis, this type is common in kids and teens and is usually triggered by strep infections. Guttate lesions look like small, pink teardrops, covered in thin scaling. Spots usually present on the torso and limbs. Unlike chronic types, a guttate outbreak can run its course in weeks. For some people, though, it evolves into plaque psoriasis.

Erythrodermic psoriasis: The least common but most dangerous type of psoriasis, affecting large sections of the body with itchy rashes that burn intensely and skin that flakes off in sheets. With high BSA involvement, people with erythrodermic psoriasis often seek care in a burn unit to manage fevers, loss of fluid, electrolytes, and proteins, and disrupted bodily functions.

Palmoplantar psoriasis (PPP): PPP is a type affecting only the palms and soles. Although limited in surface area, PPP is a high impact type since its location causes functional impairment.

Treatment terminology

Adherence/compliance: The extent to which a patient’s behavior matches their prescribed regimen. This can include taking medication as prescribed, agreed-upon lifestyle changes, and attending follow-up appointments.

Combination therapy: A care plan combining several treatment approaches.

Topical treatment: Product applied on the skin’s surface, including moisturizers, topical steroids, peeling agents, shampoos, and other nonsteroidal options like Zoryve and Vtama.

Immunosuppressant: A drug that dampens the immune system to prevent it from attacking healthy cells.

Emollient: A moisturizing substance applied topically to soothe, soften, and hydrate skin. Emollients create a protective film to limit water loss.

Systemic therapy: An immunosuppressant that acts on a broad level to limit inflammation.

Biologics: Unlike traditional systemic therapies that suppress the entire immune system, biologics are targeted drugs made of living molecules. They only affect the specific proteins known to trigger psoriasis — an approach offering better results and fewer side effects. Biologics are given via injection or infusion.

Biosimilars: Almost identical to biologic drugs, biosimilars are considered equally as safe and effective as their brand-name alternatives. These are essentially the generic versions of biologics.

Phototherapy: A type of light therapy using the same UV rays emitted by the sun to slow skin growth.

Topical steroids: Our bodies release natural hormones in response to stress (corticosteroids). Topical steroids are synthetic derivatives formulated for use on skin. With quick anti-inflammatory results, they’re prescribed for a range of concerns. The United States categorizes topical steroids into 7 potency classes. Long-term use poses serious health risks so they’re intended only for short-term relief.

FTU: A finger-tip unit (FTU) is a standardized measure to facilitate accurate topical dosing. One FTU is the amount of cream or ointment dispensed on an adult index finger from fingertip to first crease.

Bottom line

Understanding what’s going on in your chronically ill body can be empowering, not to mention critical for navigating the healthcare system with psoriasis.

The more we know, the better we can advocate for ourselves!