Generalized Pustular Psoriasis (GPP)


Generalized pustular psoriasis (GPP) is a rare and severe form of pustular psoriasis that is characterized by sudden flare-ups of painful, widespread cutaneous eruptions that spread quickly. Systemic symptoms, such as fever, malaise, fatigue, and arthritis, often accompany the dermatological manifestations of GPP. Cholangitis, epigastric discomfort, interstitial pneumonitis, oral erosions, acute renal failure, otitis media, uveitis, and osteoarthritis are among the extracutaneous symptoms and signs that have been reported.1 

Patients with GPP typically present with a rapid onset of widespread pustules on ill-defined areas of erythema and edema.2 The skin lesions are erythematous and covered with aseptic pustules, dispersed both over the lesions and along their margins. Pustules disintegrate with desquamation and collarettes of scales many weeks after the start of pustulation, ultimately leading to hyperpigmentation. Lesions often affect the entire body, and episodes frequently recur over time. 1

GPP subtypes include3

  • Von Zumbusch (also called acute GPP): diffuse generalized pustular eruptions along with systemic symptoms such as fever or arthralgia
  • Annular: annular lesions with pustules along the advancing edge
  • Exanthematic: acute pustular eruptions occurring in the absence of systemic symptoms that subside after a few days
  • Impetigo herpetiformis: pustular psoriasis occurring during pregnancy 

In the diagnostic process, histopathological examination of skin biopsy is required for confirmation of GPP.4 

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Histological Features

The majority of the histological features of GPP, especially the overall architecture, resemble that of psoriasis vulgaris (PV). These include parakeratosis (retained nuclei in the stratum corneum), hyperkeratosis (thickened stratum spinosum), diminished stratum granulosum, elongation of the rete ridges, and thinned suprapapillary epidermis.5,6 

Spongiform pustules of Kogoj are a characteristic histological feature of GPP. These form as neutrophils in the epidermis accumulate between keratinocytes, where there is spongiosis as well.2,5 Capillary dilation of the papillary dermis is also noted.5

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In addition, there are significant neutrophilic infiltrates in the papillary dermis and epidermis. These infiltrates induce basal keratinocytes to herniate into the papillary dermis, breaking the desmosomal connections of keratinocytes and causing Munro’s microabscesses to form. Superficial perivascular mononuclear cell infiltrations are also noted.2,6 

It is important to note that edema and inflammatory cell infiltrates are significantly greater in GPP than in PV.4 

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References

  1. Sussman M, Napodano A, Huang S, Are A, Hsu S, Motaparthi K. Pustular psoriasis and acute generalized exanthematous pustulosis. Medicina (Kaunas). 2021;57(10):1004. doi:10.3390/medicina57101004
  2. Fujita H, Gooderham M, Romiti R. Diagnosis of generalized pustular psoriasis. Am J Clin Dermatol. 2022;23(Suppl 1):31-38. doi:10.1007/s40257-021-00652-1
  3. Shah M, Al Aboud DM, Crane JS, Kumar S. Pustular psoriasis. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2023. Updated August 8, 2022. Accessed May 18, 2023.
  4. Ly K, Beck KM, Smith MP, Thibodeaux Q, Bhutani T. Diagnosis and screening of patients with generalized pustular psoriasis. Psoriasis (Auckl). 2019;9:37-42. doi:10.2147/PTT.S181808
  5. Cockerell CJ. Pustular psoriasis workup. Medscape. Updated October 8, 2021. Accessed May 18, 2023. 
  6. Mirza HA, Badri T, Kwan E. Generalized pustular psoriasis. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2023. Updated September 12, 2022. Accessed May 18, 2023.

Reviewed by Hasan Avcu, MD, on 5/25/2023.

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