Pustular psoriasis is characterized by merging white pustules (bubbles with non-infectious pus). Variants of pustular psoriasis are clinically distinguished. Generalized pustular psoriasis often occurs in patients with an existing or previous plaque variant of psoriasis, but can also develop in people without previous forms of psoriasis. Genetic analysis has identified mutations of the interleukin-36RN (IL36RN) and CARD14 (caspase recruitment domain) genes as important predisposing factors in the emergence of a particular form of psoriasis. The greatest number of isolated generalized pustular psoriasis cases is due to a recessive mutation of the IL36RN gene, and only a small number of cases of generalized pustular psoriasis against the background of ordinary psoriasis had the same mutation.
It leads to an idea that the isolated generalized pustular psoriasis genetically differs from the same psoriasis, which appeared in combination with ordinary psoriasis. Determination of recessive mutation of IL36RN gene leads to early diagnosis of generalized pustular psoriasis, and the mutation in the CARD14 gene predisposes to generalized pustular psoriasis and ordinary psoriasis. Generalized pustular psoriasis is characterized by widespread dark erythematous foci with clearly visible sterile pustules that merge to form vast pus lakes.
Foci of pathological changes spread very quickly, the disease is potentially life-threatening. The localized form of pustular psoriasis includes palm-sole type and persistent pustular acrodermatitis Allopo, the first of them affects the palms of hands and soles of feet, the latter usually affects the ends of the fingers, toes or both with the involvement of the nails. Ironically, tumor necrosis factor (TNF) inhibitors, which are effective in treating psoriasis, have also been associated with the debut of pustular rashes reminiscent of psoriasis and located mainly in the palms and soles.
Psoriasis in childhood
In children, psoriasis more often makes its debut in a drop-shaped form that often coincides with a previous streptococcal infection of the upper respiratory tract. Antigenic similarity between streptococcal proteins and keratinocyte antigens may explain the role of the streptococcal infection as a trigger. One third of children with droplet-shaped psoriasis will develop a plaque disease in their future lives.
Psoriasis is not uncommon in children; its prevalence varies from 0.5% to 2.0% in various studies. A recent large psoriasis study found a prevalence of 0.71% among children and adolescents in Germany aged 0 to 18 years, which increased linearly with age. Psoriasis affects areas of children’s skin that are not typical of adults, such as the face, which requires particularly neat therapeutic tactics. A full body examination, including the anogenital area, is also desirable.
Provoking factors Psoriasis can be provoked by non-specific triggers, such as mild injury (combs, piercing, tattooing), sunburn, chemical irritation. Systemic drugs such as β-blockers, lithium salts, antimalarial drugs and non-steroidal anti-inflammatory drugs can exacerbate the disease. Psoriasis can be caused or significantly worsened by professional risk factors that have a negative impact on skin barrier function. In such cases, in particular, with palm-surface psoriasis, the patient’s working environment should be assessed and adequate protective measures implemented.
HIV infection can also be a trigger for psoriasis because the prevalence of psoriasis in HIV-infected patients is the same or slightly higher than in the general population, and HIV-infected patients with existing psoriasis often have outbreaks of psoriasis that are really difficult to treat.