Generalized Pustular Psoriasis (GPP)

Generalized pustular psoriasis (GPP) is a rare skin disorder characterized by acute, subacute, and chronic episodes of pustule formation on an erythematous background. GPP is typically triggered by another condition (eg, infection, stress, pregnancy, withdrawal of corticosteroid treatment) or a medication (eg, rituximab, amoxicillin).^1,2 GPP can affect individuals at any age but most commonly develops in adults approximately 50 years old.¹ 

The subtypes of GPP vary in clinical manifestations and disease course, and attacks range in severity from those in which systemic symptoms are absent to those with life-threatening complications requiring hospitalization.² An individual may experience several flares each year or every few years. Each flare usually lasts for 2 to 5 weeks, although sometimes longer.³

General Systemic Signs and Symptoms

Patients with GPP typically present with a high-grade fever (up to 40°C) and general malaise.^1,2 Often, they appear distressed, tachypneic, and tachycardic. They may also have headache, chills, and nausea.⁴ 

Laboratory abnormalities consist of neutrophilic leukocytosis, C-reactive protein elevation, abnormal liver test values, and peripheral eosinophilia.^1,2 Pregnant patients may have fever, delirium, diarrhea, vomiting, and tetany.¹

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Cutaneous Symptoms

The hallmark feature of GPP is the presence of numerous, small, sterile pustules on the skin, usually 2 to 3 mm in size. The areas of skin where the pustules develop are painful and erythematous.¹ The eruption may last for days or weeks, causing discomfort and exhaustion.⁴

Lesions in GPP can develop on the trunk, extremities, and less commonly the face.⁴ Pustules and scaling may develop along the periphery of circinate or annular erythematous plaques.⁴ In pregnant women, the erythematous plaques are usually symmetric and located in flexural areas. New pustules may develop at plaque boundaries while older pustules form scales or crusts in the center.¹ 

Flares of GPP with cutaneous symptoms can cause pain, a burning sensation, and pruritus.⁵ The oropharyngeal mucosa may be affected, and a geographic or fissured tongue causing dysphagia, cheilitis, and ocular involvement (conjunctivitis, uveitis, iritis) may be present.^4,5

GPP typically exhibits a pattern of spontaneous, self-remitting disease flares that occur weeks after an attack begins. However, skin lesions can persist between attacks.²

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GPP is more likely to develop in patients with localized pustular psoriasis, such as palmoplantar pustular psoriasis and acrodermatitis continua of Hallopeau (ACH). In palmoplantar pustular psoriasis, the formation of pustules on the palms and soles leads to hyperkeratosis and skin fissuring. In ACH, pustules also form on the digits and may spread to the hands, forearms, and feet.^1,2

In patients with concomitant psoriasis vulgaris, sterile pustules may erupt on pre-existing plaques that are typical of psoriasis vulgaris.¹

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Extracutaneous Symptoms

Because of the systemic nature of GPP, extracutaneous manifestations may develop. These include nail abnormalities (resulting in onychodystrophy, onycholysis, and defluvium unguium), jaundice, arthralgia, lower extremity edema, cholestasis, cholangitis, epigastric pain, arthritis, interstitial pneumonitis, oral lesions, otitis media, and polymyalgia.^1,2,4,5 

Potentially life-threatening extracutaneous complications include sepsis and renal, hepatic, respiratory, and cardiac failure. The mortality rate associated with these complications ranges from 2% to 16%.³

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References

1. Hoegler KM, John AM, Handler MZ, Schwartz RA. Generalized pustular psoriasis: a review and update on treatment. J Eur Acad Dermatol Venereol. 2018;32(10):1645-1651. doi:10.1111/jdv.14949
2. Bachelez H. Pustular psoriasis: the dawn of a new era. Acta Derm Venereol. 2020;100(3):adv00034. doi:10.2340/00015555-3388
3. Rivera-Díaz R, Daudén E, Carrascosa JM, Cueva P, Puig L. Generalized pustular psoriasis: a review on clinical characteristics, diagnosis, and treatment. Dermatol Ther (Heidelb). 2023r;13(3):673-688. doi:10.1007/s13555-022-00881-0
4. Cockerell CJ. Pustular psoriasis clinical presentation. Medscape. Updated October 8, 2021. Accessed May 11, 2023.
5. 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

Reviewed by Harshi Dhingra, MD, on 5/30/2023.

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Diana Diez Gaspar, PharmD, PhD

Diana earned her PhD and PharmD with distinction in the field of Medicinal and Pharmaceutical Chemistry at the Universidade do Porto. She is an accomplished oncology scientist with 10+ years of experience in developing and managing R&D projects and research staff directed to the development of small proteins fit for medical use.