Pustular flare after biologic withdrawal: who is at risk, and what it looks like

Design

Multicentre retrospective cohort with generalised estimating equations

Population

1,198 biologic withdrawal episodes in responders with plaque psoriasis, 2011 to 2025

Primary outcome

Distinct pustular psoriasis flare after withdrawal

Effect

86 of 1,198 episodes (7.2%); risk rose with withdrawal-relapse cycles

A multicentre cohort examined 1,198 episodes in which patients with plaque psoriasis responded to a biologic and then stopped it, between 2011 and 2025.

In 86 episodes (7.2%), stopping was followed by a distinct pustular flare: painful, diffuse, intense redness with pustules and swelling, mainly on the lower legs. The risk rose with each cycle of stopping and relapsing. Independent associations were a family history of psoriasis, psoriatic arthritis, a previous flare of this type, more previous withdrawal-relapse cycles, and taking longer to reach a 50% improvement in psoriasis severity on the biologic.

The study was non-randomised and lacked histology or molecular data, so this flare phenotype is described clinically rather than defined biologically.

In Indian practice, biologics are often stopped and restarted because of cost or supply, which is exactly the pattern this study links to rising risk. Where a break is unavoidable, the risk factors identify the patients to warn and see early.

• Before stopping a biologic, check for a family history of psoriasis, psoriatic arthritis and any previous pustular flare.
• Count previous stop-start cycles: risk rose with each one.
• Warn at-risk patients to report painful red swelling with pustules on the legs promptly.
• Plan early restart for at-risk patients rather than waiting for a full plaque relapse.
• Where cost forces a break, consider these risk factors when deciding who to prioritise for continuous treatment.

Why it matters

Stopping and restarting biologics is common, and each cycle may make the next relapse more severe rather than simply returning to baseline.

Don't overread it

This was an observational cohort without histology; it describes who flared, not whether continuous treatment prevents it.

The statistics, in plain English

A 7.2% rate means about 1 in 14 withdrawal episodes was followed by this flare. The risk factors come from a model that accounts for repeated episodes in the same patient, but without randomisation they identify association, not cause.

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