What is pustular psoriasis?

Pustular psoriasis is a rare type of psoriasis that presents with small pimple-like eruptions that are filled with pus. It can occur in different forms, such as localized palmoplantar pustulosis, which mainly affects the palms of the hands and soles of the feet, and generalized pustular psoriasis, which affects large areas all over the body.¹

While pustular psoriasis often develops in association with or arises from a more common type of psoriasis, plaque psoriasis, newer studies have shown that it may actually represent a new and separate genetic autoinflammatory disease.² Factors related to the development of this type of psoriasis include different medications, infection, injury to the skin, smoking and heavy alcohol consumption, and pregnancy.³

Symptoms

The course of pustular psoriasis can be unstable and lengthy without treatment, alternating between periods of recurrence and remission.⁴ Generally, episodes of pustular psoriasis occur rapidly. First, the skin gets red and tender, then whitish-yellow, pus-filled blisters appear a few hours later. The pus, which is made up of white blood cells, is not an infection and will not spread from one person to another. In a few days, the blisters will dry and form scales.

Diagnosis

Diagnosing patients with suspected pustular psoriasis includes a full medical history and review of symptoms, total body skin examination, and a possible skin biopsy or blood work if the diagnosis is unclear.⁵ If there is concern, a skin or blood culture may be done.

Treatment

Patients who present with pustular psoriasis can sometimes appear systemically unwell, so an admission to the hospital may be necessary to ensure adequate supportive care. In this case, measures to soothe the skin, such as moisturizers, wet wraps, or oatmeal baths can help with symptom control.⁶ Medical treatment for pustular psoriasis includes oral therapies, topical therapies, and phototherapy. Oral therapies, like methotrexate or acitretin, are typically first-line in the initial management of the disease because topical treatments or phototherapy can take time to work.⁴

References

1. Robinson A, Van Voorhees AS, Hsu S, et al. Treatment of pustular psoriasis: from the Medical Board of the National Psoriasis Foundation. J Am Acad Dermatol. 2012;67(2):279-288.
2. Benjegerdes KE, Hyde K, Kivelevitch D, Mansouri B. Pustular psoriasis: pathophysiology and current treatment perspectives. Psoriasis (Auckl). 2016;6:131-144.
3. Choon SE, Lai NM, Mohammad NA, Nanu NM, Tey KE, Chew SF. Clinical profile, morbidity, and outcome of adult-onset generalized pustular psoriasis: analysis of 102 cases seen in a tertiary hospital in Johor, Malaysia. Int J Dermatol. 2014;53(6):676-684.
4. Fujita H, Terui T, Hayama K, et al. Japanese guidelines for the management and treatment of generalized pustular psoriasis: The new pathogenesis and treatment of GPP. The Journal of Dermatology. 2018;45(11):1235-1270.
5. Kardaun SH, Kuiper H, Fidler V, Jonkman MF. The histopathological spectrum of acute generalized exanthematous pustulosis (AGEP) and its differentiation from generalized pustular psoriasis. J Cutan Pathol. 2010;37(12):1220-1229.
6. Varman KM, Namias N, Schulman CI, Pizano LR. Acute generalized pustular psoriasis, von Zumbusch type, treated in the burn unit. A review of clinical features and new therapeutics. Burns. 2014;40(4):e35-e39.