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Friday 14 November 2003

cutaneous psoriasis


- neutrophils in stratum corneum in psoriasis, vs. pustule of Kogoj in stratum spinosum


The biopsy shows psoriasis, based on these findings: 1) parakeratosis with 2) an absent granular layer, 3) acanthosis (hyperplasia / overgrowth of the epidermis) most prominent at the rete ridges, 4) dermal chronic inflammation and prominent capillaries.

Another common finding is 5) neutrophils in the parakeratotic epidermis - called Munro microabscesses. The patient frequently has a scaly, silver rash.

A major clue to psoriasis is parakeratosis with an ABSENT GRANULAR LAYER. Other findings include prominent rete ridges, prominent dermal capillaries and inflammation, and Munro microabscesses - neutrophils in the parakeratotic epidermis.

-  epidermal anomalies in psoriais
- ungueal anomalies in psoriasis


- seen in up to 50% of psoriasis patients, more common in patients with psoriatic arthropathy
- histopath -> psoriasiform onychitis with spongiform pustulation, negative fungal special stains (see photos)
- differential -> onychomycosis, eczematous onychitis, Reiter syndrome

Susceptibility loci

- PSORS1 locus at 6p21 (12148091)
- IL12B variants (17236132)
- IL23R variants (17236132)


- Schon MP, Boehncke WH. Psoriasis. N Engl J Med. 2005 May 5;352(18):1899-912. PMID: 15872205

- Gottlieb AB. Psoriasis: emerging therapeutic strategies. Nat Rev Drug Discov. 2005 Jan;4(1):19-34. PMID: 15688070

- Bowcock AM, Cookson WO. The genetics of psoriasis, psoriatic arthritis and atopic dermatitis. Hum Mol Genet. 2004 Apr 1;13 Spec No 1:R43-55. PMID: 14996755

- Bhalerao J, Bowcock AM. The genetics of psoriasis: a complex disorder of the skin and immune system. Hum Mol Genet. 1998;7(10):1537-45. PMID: 9735374


- Cargill M, Schrodi SJ, Chang M, Garcia VE, Brandon R, Callis KP, Matsunami N, Ardlie KG, Civello D, Catanese JJ, Leong DU, Panko JM, McAllister LB, Hansen CB, Papenfuss J, Prescott SM, White TJ, Leppert MF, Krueger GG, Begovich AB. A large-scale genetic association study confirms IL12B and leads to the identification of IL23R as psoriasis-risk genes. Am J Hum Genet. 2007 Feb;80(2):273-90. PMID: 17236132