A 27-year-old gentleman was admitted for fever and generalised pustular eruption for 2 days

Dr. Adrian KC Cheng

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Clinical history:

A 27-year-old gentleman was admitted for fever and generalised pustular eruption for 2 days. He had a history of psoriasis with psoriatic arthropathy involving both axial and peripheral joints since childhood. His previous treatment include acitretin and methotrexate. Adalimumab subcutaneous injection was started three years ago for worsening of spondylarthritis as evidenced in his magnetic resonance imaging. He denied any use of systemic corticosteroid or other medications. He had a fever up to 39°C. Dermatological examination revealed polycyclic and annular erythematous plaques with coalescing pustules at the advancing edge over his chest, abdomen, arms and legs. There was central clearing in some of the lesions with crusts and trailing scales. Blood tests on admission showed mild neutrophilia. Serum bilirubin and transaminases were elevated to around two times the upper limit of normal. Ultrasonography showed no evidence of biliary obstruction.

What is the diagnosis?

Answer:
D. Generalised pustular psoriasis

Generalised pustular psoriasis (GPP) is a rare and potentially life-threatening form of psoriasis. Patients with acute GPP experience the rapid onset of painful, widespread red patches covered with numerous pinhead-sized pustules, which may merge into larger collections. Alongside these skin changes, individuals often feel generally unwell, experiencing fever, chills, and other symptoms such as joint pain, lower limb swelling, liver dysfunction, and eye inflammation. Infections, pregnancy, and rapid tapering of systemic corticosteroids, can trigger or worsen GPP. If left untreated, the disease can escalate and become lifethreatening. There is significant clinical and histopathological overlap between GPP and acute generalised exanthematous pustulosis (AGEP). Both conditions are characterised by non-follicular sterile pustules. Most cases of AGEP are drug-induced. Commonly associated drugs include aminopenicillins, cephalosporins, and diltiazem. AGEP may occasionally be due to other causes, like infection. Lesions usually last one to two weeks and are followed by superficial desquamation. AGEP is typically a one-time episode that resolves after stopping the offending drug. Recurrence is rare unless that the patient is re-exposed to the same medication. No personal history of psoriasis, rapid appearance, and recent drug exposure would favour AGEP. Patients with GPP may appear systemically unwell, and hospitalisation is often necessary to ensure adequate supportive care and rule out systemic infection. Patients with GPP may have recurrent disease flare and require maintenance treatment. Treatment options include acitretin, methotrexate, cyclosporine, and various biologic therapies including TNF-alpha inhibitors, IL-17 inhibitors, IL-23 inhibitors, and IL-36 inhibitors. We hope to increase the awareness of generalised pustular psoriasis among health care professionals in Hong Kong. Early recognition and hospitalisation of patients with suspected GPP could improve the outcome of this potentially lethal dermatological condition.

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