How does the Generalized Pustular Psoriasis Physician Global (GPPGA) work?

How does the GPPGA work?

The Generalized Pustular Psoriasis Physician Global Assessment (GPPGA) is a tool developed to assess the severity of Generalized Pustular Psoriasis (GPP)¹. It evaluates the key cutaneous manifestations of GPP, namely erythema, scaling, and pustulation¹. The GPPGA is an adaptation of the Physician Global Assessment (PGA), where induration in PGA is replaced by pustulation for GPPGA¹.

How do you calculate the GPPGA score?

The GPPGA score is calculated based on the assessment of erythema, pustules, and scaling¹. Each of these components is evaluated, and their scores are combined to determine the total GPPGA score¹.

What is the formula for the GPPGA?

The formula for calculating the GPPGA score is: Composite mean score = (erythema + pustules + scaling)/3; The total GPPGA score is given as follows¹:

0 if the mean is 0 for all three components;
1 if 0 < mean < 1.5;
2 if 1.5 ≤ mean < 2.5;
3 if 2.5 ≤ mean < 3.5;
4 if mean ≥ 3.5.

What are the limitations of the GPPGA?

The limitations of the GPPGA include:

It may be more confidently assessed by experienced dermatologists, potentially leading to variability in scoring among less experienced clinicians.
Assessments are based on photographs rather than direct patient examination, which could limit the scope of evaluation.
There may be a lack of variation in skin phototypes among patient images in the studies.
The rarity and episodic nature of GPP, along with the severity of flares, pose challenges in developing comprehensive and accurate disease measures.

References

Burden AD, et al. Am J Clin Dermatol. 2022;23(Suppl 1):39-50.