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Psoriasis Severity: More Than Just a Score Card
While Psoriasis Area and Severity Index (PASI) offers great utility in clinical trials, grading severity is not as cut-and-dry in the examination room. Quality of life (QoL) should also be considered when measuring disease severity and creating a treatment plan for patients, especially since QoL can heavily influence how patients with psoriasis perceive their disease.
Framing Severity by QoL
Psoriasis is not just a skin condition. The inflammation impacts other organ systems, including the joints.1,2 While psoriatic arthritis is a well-known component of psoriatic disease, other comorbid medical conditions exist including cardiovascular disease, inflammatory bowel disease, and mental health conditions.3-5
When selecting therapies to treat psoriasis, we should also consider choosing a medication that is safe, effective, and compatible with the patient’s comorbidities. For example, not all psoriasis medications also treat psoriatic arthritis. We must be aware of the overall impact psoriatic disease has on a patient’s health and well-being. Treatment plans need to take into account the whole person, not just their skin and joints.6
The National Psoriasis Foundation (NPF) has conducted surveys to better understand the impact of psoriatic disease on patients.7 We know that psoriasis impacts the emotional well-being of nearly 90% of the population with psoriasis.8 Dermatologists need to be aware of the impact of psoriatic diseases on mental health, ask their patients about how they are coping with their disease, and help connect them with any needed resources. Patients can have diminished QoL for many reasons, including frustration with delay in diagnosis or lack of disease control, a fear of outbreaks once their disease is controlled, and social embarrassment where individuals feel a need to constantly cover up.
As psoriasis health care providers, we need to understand what is preventing our patients from living their day-to-day lives, functioning optimally at work, and maintaining strong, healthy relationships with those around them. Taking the above into consideration as well as patients’ disease severity score will help us create a personalized and tailored treatment plan and set expectations for what we hope to accomplish with that treatment plan.
There are certain areas that psoriasis can affect where I find that the patient-reported disease severity and patient distress about their psoriasis is often out of proportion to what the PASI score would show. When psoriasis is on the trunk or extremities, a long-sleeve shirt or pants can often cover it up. However, when psoriasis affects the nails, it is less easily hidden, especially for those who may not use nail polish. Nail psoriasis can really impact patients’ QoL and for some is particularly bothersome when they interact with others at work, such as when shaking hands. Several patients have come to me distressed about having mild or no disease elsewhere, but they are so impacted by having nail psoriasis.10
Other areas affected by psoriasis that might be more visible and challenging to cover up include the ears, scalp, and neck along the scalp hairline. Further, ear and scalp psoriasis can be very itchy and flaky. Psoriasis in these areas may affect only a small portion of overall body surface area (BSA), yet those areas can have major impacts on patient QoL.
Measuring Severity Beyond PASI
The Psoriasis Area and Severity Index (PASI) is one way to measure psoriasis disease severity. The PASI score is routinely used in clinical trials to determine the severity of psoriasis at the initiation of a trial and then throughout the trial to track disease severity over time. The PASI takes into account psoriasis plaque characteristics (ie, erythema, induration, and scaling) as well as the surface area affected by psoriasis in different regions of the body.12 Determining disease severity using the PASI is valuable because it is a validated tool that we are used to seeing in outcomes for clinical trials. However, practically speaking, the PASI is more challenging to implement in a busy office setting. Other easier tools to mea- sure psoriasis disease severity in the clinic include body surface area (BSA) score or the Investigator Global Assessment (IGA).
The BSA is the percentage of the total skin affected by psoriasis. A total of 1% BSA is roughly equivalent to one of the patient’s palms, including fingers. Mild psoriasis disease severity is defined as less than 3% BSA, moderate psoriasis is 3% to 10% BSA, and severe psoriasis is more than 10% BSA involvement. The NPF treat- to-target guidelines state that the target response is less than or equal to 1% BSA involvement by 3 months of treatment.11 The BSA is something the dermatologist can implement in a busy practice to gauge whether their patients are achieving treatment goals. The 5-point IGA is the physician’s determination of disease severity on a scale of 0 (skin is clear) to 4 (severe skin disease). The score is based on assessment of psoriasis plaque thickness, intensity of redness, and quality of scale. My goal is that patients achieve a score of 0 or 1 (almost clear) while on treatment. On the logistical side of things, tracking and documenting BSA and IGA can also help with insurance approvals and renewals for systemic medications.
For tracking QoL, the Dermatology Life Quality Index (DLQI) is a validated dermatology-specific and user-friendly questionnaire. It is composed of 10 questions that are answered by the patient and is scored from 0 to 30. Higher scores indicate greater disease impact on QoL. It is applicable to psoriasis as well as many other skin diseases. The DLQI, along with the above physician-determined disease severity scores, can help inform a conversation about treatment.
Conclusion
Disease severity tools would indicate there is way to easily define patients as having mild, moderate, or severe psoriasis. I would argue that these numbers in addition to other factors, including the patient’s QoL, need to be considered when evaluating patients’ psoriasis disease severity and selecting treatment. Even if someone has mild disease severity by BSA or a PASI score, this may not match the degree of the impact of psoriasis on the patient’s QoL. In addition, a treatment plan should be developed in the context of the patient’s comorbidities, patient preferences for treatment, and through shared decision making. Measuring improvement during treatment with scores like PASI or BSA is just one method we can use.12
One of the best things we can do for patients with psoriasis is to be aware of all of the potential impacts of their disease in order to care for the whole patient and provide a comprehensive treatment plan.
1. When psoriatic disease strikes the hands and feet. National Psoriasis Foundation. June 12, 2019. Accessed February 15, 2022. https://www.psoriasis.org/advance/ when-psoriatic-disease-strikes-the-hands-and-feet/
2. Getting to the heart of psoriasis. National Psoriasis Foundation. February 4, 2021. Accessed February 15, 2022. https://www.psoriasis.org/advance/getting-at-the- heart-of-psoriasis/
3. Teixeira A, Ribeiro C, Gaio R, et al. Influence of psoriasis lesions’ location and severity on psychosocial disability and psychopathology. Observational study and psychometric validation of the SAPASI Portuguese version. J Psychosom Res. 2022;154:110714. doi:10.1016/j.jpsychores.2021.110714
4. Wang Q, Lu W, Luo Y, et al. Relationship between patient acceptable symptom state and disease scores in psoriasis. J Dermatol. Published online January 25, 2022. doi:10.1111/1346-8138.16299
5. Kowalewska B, Krajewska-Kułak E, Sobolewski M. The impact of stress-coping strategies and the severity of psoriasis on self-esteem, illness acceptance and life satisfaction. Dermatol Ther (Heidelb). Published online January 18, 2022. doi:10.1007/s13555-021-00669-8
6. Psoriasis guidelines. National Psoriasis Foundation. Accessed February 15, 2022. https://www.psoriasis.org/psoriasis-guidelines/
7. Armstrong AW, Schupp C, Wu J, Bebo B. Quality of life and work productivity impairment among psoriasis patients: findings from the National Psoriasis Foundation survey data 2003-2011. PLoS One. 2012;7(12):e52935. doi:10.1371/journal. pone.0052935
8. Feldman SR, Goffe B, Rice G, et al. The challenge of managing psoriasis: unmet medical needs and stakeholder perspectives. Am Health Drug Benefits. 2016;9(9):504- 513. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5394561/
9. Stewart CR, Algu L, Kamran R, et al. The impact of nail psoriasis and treatment on quality of life: a systematic review. Skin Appendage Disord. 2021;7(2):83-89. doi:10.1159/000512688
10. Mental health and psoriasis severity assessment. National Psoriasis Foundation. March 31, 2021. Accessed February 15, 2022. https://www.psoriasis.org/advance/ mental-health-and-psoriasis-severity-assessment/
11. Armstrong AW, Siegel MP, Bagel J, et al. From the Medical Board of the National Psoriasis Foundation: Treatment targets for plaque psoriasis. J Am Acad Dermatol. 2017;76(2):290-298. doi:10.1016/j.jaad.2016.10.017
12. Nageen S, Shah R, Sharif S, Jamgochian M, Waqas N, Rao B. Platelet count, mean platelet volume, and red cell distribution width as markers for psoriasis severity. J Drugs Dermatol. 2022;21(2):156-161. doi:10.36849/jdd.6127
