Pustular psoriasis in Child
Pustular psoriasis flares can be induced by infection (Trichophyton rubrum, cytomegalovirus, Streptococcus spp, varicella-zoster, and Epstein-Barr virus), a rapid withdrawal of corticosteroids, pregnancy, medications (NSAIDs, lithium, potassium iodine, trazodone, penicillin, interferon, and hydroxychloroquine), and topical irritants such as tar and anthralin. More recently, COVID-19 infection has been shown to trigger a pustular flare in a 12-year-old with prior plaque psoriasis in remission.
While tumor necrosis factor (TNF)-alpha antagonists such as infliximab and adalimumab are used to treat pustular psoriasis, they have also been reported paradoxically to induce it. Anti-IL-12/23 agents such as ustekinumab, anti-IL-23, and anti-IL-17 agents induce significant improvement for some patients. Targeted therapy aimed at IL-36 (eg, spesolimab, which is approved for use in adults) has been demonstrated to rapidly improve pustular psoriasis regardless of IL36RN mutation status.
There are 3 subtypes of generalized pustular psoriasis:
- von Zumbusch type – Acute onset of generalized erythema and pustules with systemic manifestations including fever, skin tenderness, malaise, arthralgias, headache, and nausea. After several days, the pustules resolve to become confluent, scaling plaques.
- Exanthematic type – Acute onset of small pustules that are triggered by an infection or a drug. This subtype usually lacks systemic symptoms.
- Annular subtype – Erythematous, annular lesions that have pustules at the advancing edge of a lesion and is associated with fever, malaise, and other systemic manifestations.
Extracutaneous manifestations of pustular psoriasis may be severe and are associated with a great deal of morbidity and mortality. The most common extracutaneous manifestations of pustular psoriasis include cholestasis, cholangitis, arthritis, intestinal pneumonitis, oral lesions, and acute renal failure. Electrolyte disturbances such as hypocalcemia may occur and can be life-threatening. Lesions may also become superinfected.
Pustular psoriasis in children often has a more benign course than in adults, and children have a higher rate of spontaneous remission of generalized pustular psoriasis. Pediatric pustular psoriasis may be part of SAPHO syndrome (synovitis, acne, psoriasis / palmoplantar pustulosis, hyperostosis, osteitis).
L40.1 – Generalized pustular psoriasis
200973000 – Pustular psoriasis
- AGEP – Clinically indistinguishable from pustular psoriasis. Time of onset and a drug history may help differentiate AGEP from pustular psoriasis. Antibiotics are the likely causative agents in AGEP. Histology can also help differentiate between those diagnoses. Also look for high fever, edema of the face, pustular eruption that occurs shortly after drug administration (fewer than 2 days), marked serum leukocytosis with neutrophilia, and associated petechiae, purpura, and vesicles in AGEP.
- Toxic epidermal necrolysis (TEN)
- Drug reaction with eosinophilia and systemic symptoms (DRESS) – Look for marked eosinophilia, visceral involvement (most commonly hepatitis), less acute onset, facial edema, and atypical lymphocytosis.
- Subcorneal pustular dermatosis (Sneddon-Wilkinson disease) – Associated with immunoglobulin A (IgA) paraproteinemia and is very responsive to dapsone. Pustular psoriasis is not responsive to dapsone and does not have an IgA paraproteinemia.
- Deficiency of interleukin-36 receptor antagonist (DITRA) syndrome
- Deficiency of the interleukin-1 receptor antagonist (DIRA) features generalized pustular psoriasis, sterile multifocal osteomyelitis, and periostitis.
- Keratoderma blennorrhagicum seen in reactive arthritis disease – Look for characteristic associated findings including urethritis, arthritis, and ocular findings.
- Dyshidrotic eczema – Extremely pruritic, restricted to hands and feet. Look for deep-seated vesicles that look like tapioca pudding. Consider as differential for palmoplantar pustulosis.
- Erythema annulare centrifugum – To be considered when annular-type psoriasis is observed. No associated systemic findings. Individual lesions can last for months.
- Disseminated herpes simplex
- Netherton syndrome features ichthyosis linearis circumflexa, which may resemble annular pustular psoriasis, especially if staphylococcal superinfection is also present.
- Carvajal syndrome caused by mutations in desmoplakin may also feature a generalized pustular eruption indistinguishable from generalized pustular psoriasis.