Types and Causes of Psoriasis
Table of Contents
In psoriatic skin, changes in keratin are observed. Specifically, changes from K10 to K16 and K17 occur, resulting in scaling, hyperkeratosis, and increased thickness of the epidermal layer.
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:
- Raised plaques
- Adherent scales
- Erythematous plaques
The following histological findings are observed:
- Acanthosis
- Parakeratosis
- Telangiectasis
Types of Psoriasis
- Psoriasis vulgaris (common psoriasis)
- Guttate psoriasis (guttate psoriasis)
- Erythrodermic psoriasis (erythrodermic psoriasis)
- Pustular psoriasis (pustular psoriasis)
- Palmoplantar pustulosis (palmoplantar pustulosis)
- Scalp psoriasis (scalp psoriasis)
- Inverse psoriasis (inverse psoriasis)
- Nail psoriasis (nail psoriasis)
- Psoriatic arthritis (psoriatic arthritis)
Changes in Keratin and Their Causes
Changes in keratin types in the epidermal layer are observed in psoriatic skin, with a characteristic increase in K17. Keratinocytes are activated by cytokines such as interferon gamma, interleukin 17a, and 22, and K17 gene expression increases through the STAT1/3 pathway. This K17 in turn activates DCs, Th1 cells, etc., 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 Atopic Dermatitis
Psoriasis and atopic dermatitis show differences in Th cell types and cytokine profiles. This affects the pathological 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, changes in keratinocyte gene expression are caused by autoimmune changes, which manifest as psoriatic changes in the epidermal layer. This is a major difference between atopic dermatitis and psoriasis.
