Psoriasis Types and Causes
Table of Contents
In psoriatic skin, changes in keratin are observed. Specifically, a shift from K10 to K16 and K17 occurs, leading to hyperkeratosis, acanthosis, and increased epidermal thickness.
Jin, L., & Wang, G. (2013). Keratin 17: A Critical Player in the Pathogenesis of Psoriasis. Medicinal Research Reviews, 34(2), 438–454. doi:10.1002/med.21291
Major Symptoms and Histological Findings of Psoriasis
The major symptoms of psoriasis include the following:
- Raised plaques
- Adherent scales
- Erythematous plaques
The following characteristics are observed as histological findings:
- Acanthosis
- Parakeratosis
- Telangiectasis
Various Types of Psoriasis
- Psoriasis vulgaris (심상성 건선)
- Guttate psoriasis (물방울 건선)
- Erythrodermic psoriasis (홍피성 건선)
- Pustular psoriasis (농포성 건선)
- Palmoplantar pustulosis (수장족저 농포증)
- Scalp psoriasis (두피 건선)
- Inverse psoriasis (간찰부 건선)
- Nail psoriasis (조갑 건선)
- Psoriatic arthritis (건선성 관절염)
Changes in Keratin and Their Causes
A shift in keratin types within the epidermal layer is observed in psoriatic skin, with a characteristic increase in K17. Keratinocytes are activated by cytokines such as interferon gamma, interleukin 17a, and 22, leading to increased K17 gene expression via the STAT1/3 pathway. This K17, in turn, activates DCs and Th1 cells, among others, accelerating changes in keratin composition.
Takahashi, T., & Gallo, R. L. (2017). The Critical and Multifunctional Roles of Antimicrobial Peptides in Dermatology. Dermatologic Clinics, 35(1), 39–50. doi:10.1016/j.det.2016.07.006
Differences Between Psoriasis and Atopy
Psoriasis and atopy differ in their Th cell types and cytokine profiles, which influences their respective pathophysiological changes.
Guttman-Yassky, E., & Krueger, J. G. (2017). Atopic dermatitis and psoriasis: two different immune diseases or one spectrum? Current Opinion in Immunology, 48, 68–73. doi:10.1016/j.coi.2017.08.008
In conclusion, in psoriasis, autoimmune changes lead to altered gene expression in keratinocytes, which manifests as psoriatic changes in the epidermal layer. This is a key difference between atopy and psoriasis.