Pustular psoriasis appears as small, yellowish, pus-filled bumps sitting on top of red, inflamed skin. Unlike the thick silvery scales of common plaque psoriasis, this form is defined by clusters of visible pustules, typically less than 5 to 10 mm across, that can merge together into larger patches. The pustules are sterile, meaning they contain inflammatory cells rather than bacteria, even though they look like they could be infected.
How the Pustules Look Up Close
The earliest sign is red patches or raised spots that quickly develop into superficial, yellowish pustules. The yellow color comes from the buildup of white blood cells beneath the skin’s surface, not from infection. These pustules sit on a background of bright red, inflamed skin, creating a distinctive contrast that sets this condition apart from other rashes.
The pustules themselves are shallow and fragile. They can appear as individual bumps scattered across inflamed skin, or they can cluster together and merge into larger sheets of pus-covered redness. When multiple pustules run together, the result looks like a lake of yellowish fluid sitting just beneath the surface. Over time, the pustules dry out, the skin peels and flakes off, and a brownish discoloration often remains where the pustules were. This cycle of redness, pustule formation, peeling, and discoloration can repeat in waves.
Generalized vs. Localized Forms
What pustular psoriasis looks like depends heavily on which type you’re dealing with. The two main forms affect very different areas of the body and carry very different levels of severity.
Generalized Pustular Psoriasis
The generalized form, sometimes called von Zumbusch psoriasis, is the more dramatic presentation. Large areas of the body turn fiery red, and within hours, hundreds of tiny pustules erupt across the inflamed skin. The torso, arms, and legs are commonly affected, and the pustules can appear in wave after wave. The skin looks raw and angry between flares, and as one round of pustules dries and peels, another round may already be forming.
This form is not just a skin problem. Between 24% and 96% of people experience high fever (above 100.4°F) during a flare. Fatigue and general malaise affect virtually all patients. Chills, nausea, diarrhea, and joint pain can accompany the skin eruption. Severe flares can become life-threatening if they disrupt the body’s ability to regulate temperature, maintain fluid balance, or fight secondary infections. The widespread skin damage can also lead to dangerous drops in calcium and protein levels.
Palmoplantar Pustulosis
The localized form most commonly targets the palms of the hands and soles of the feet. It looks like clusters of small, pus-filled blisters dotting thick, scaly, discolored skin. Fresh pustules appear yellowish, then gradually turn brown as they dry out, leaving behind flaking and peeling skin. At any given time, you might see new yellow pustules, older brown ones, and areas of dry, cracked scaling all on the same palm or sole.
This form tends to be chronic and recurring rather than acutely dangerous. It affects women roughly 3.5 times more often than men, with the average onset around age 44. While it doesn’t carry the systemic risks of the generalized form, the location on hands and feet makes it particularly disabling for daily tasks like walking, gripping, and standing.
How It Feels
The affected skin is typically tender and itchy. During active flares of generalized pustular psoriasis, the skin can feel hot to the touch and intensely sore, almost like a burn. The palmoplantar form causes deep, persistent soreness on the hands and feet, especially when the skin cracks. Walking or using your hands for routine tasks can become painful during a flare. Joint pain affects roughly one-third of people with generalized flares.
How It Differs From Infected Skin
Pustular psoriasis is one of the most commonly mistaken skin conditions because the pus-filled bumps look like a bacterial infection at first glance. There are a few key visual differences. Infectious pustules, like those from staph bacteria or folliculitis, tend to be centered around hair follicles, feel warm and tender in a focused spot, and may produce thicker, opaque pus. They can also progress to abscesses.
Psoriasis pustules, by contrast, appear on a widespread background of red, inflamed skin rather than popping up around individual hair follicles. They tend to be more uniform in size and distribution, and the surrounding redness extends well beyond the individual bumps. The cyclical pattern is also distinctive: psoriasis pustules erupt, dry, peel, and then erupt again in the same areas, while a bacterial infection generally worsens in one direction without that drying-and-peeling cycle.
What Triggers a Visible Flare
The most well-documented trigger for a pustular flare is the withdrawal of systemic corticosteroids. Someone taking oral steroids for another condition, or even for plaque psoriasis itself, can develop an explosive pustular eruption when the medication is tapered or stopped abruptly. Other known triggers include infections, severe sunburns, and certain medications like lithium, beta-blockers, and antimalarials. Triggers are reported in 41% to 85% of generalized flares, meaning some episodes appear without a clear cause.
Between 31% and 78% of people who develop generalized pustular psoriasis already have a history of plaque psoriasis. For these individuals, a flare may begin as a worsening of their existing plaques before the characteristic pustules emerge at the edges of or on top of older plaques.