Psoriasis: Symptoms, Causes, Treatment

In psoriasis – colloquially called psoriasis – (synonyms: Acrodermatitis continua pustulosa; Acrodermatitis continua suppurativa; Acrodermatitis perstans; ICD-10 L40.-: Psoriasis) is a systemic disease that includes skin symptoms (irregularly circumscribed inflammatory and scaly papules/nodules; predominantly on the knees, elbows, and scalp), possible joint involvement, and characteristic comorbidities.

Psoriasis is a common disease.

The following forms of psoriasis can be distinguished:

  • Psoriasis vulgaris type I – positive family history and clear association with HLA-Cw6; accounts for 60-70% of all psoriasis cases.
  • Psoriasis vulgaris type II – often negative family history and less pronounced association to genetic markers; 30-40% of cases.

Other forms of psoriasis occurrence are:

  • Psoriasis arthropathica (arthritis psoriatrica; psoriatic arthritis, PsA) – occurrence of the described skin changes with simultaneous arthritis (joint inflammation) of the small joints such as the finger or toe joints; accounts for 20% of cases.
  • Psoriasis pustulosa – occurrence of pustules (pustule) in the course of acute psoriasis; 0.5-2.5% of cases.

Sex ratio: men and women are equally affected.

Frequency peak: psoriasis vulgaris type I first appears predominantly before the age of 40. Psoriasis vulgaris type II manifests after the age of 40 (late type).

The prevalence (disease frequency) is 1-2% (in western industrialized countries). In childhood, the prevalence of psoriasis vulgaris increases linearly from 0.12% in infants to 1.2% in 17-year-olds.

Course and prognosis: Psoriasis progresses in episodes and is considered a benign skin disease. It is not curable, but can be treated well with adequate pharmacotherapy (drug treatment). Psoriasis vulgaris type I tends to be more severe, while type II takes a milder course. 90% of patients develop a chronic course.

Psoriatic arthritis (PsA; inflammatory disease of the joints caused by psoriasis) affects about 5-15 % of all psoriasis patients; sometimes it precedes the skin disease; about 66 % of psoriatic arthritis patients have nail psoriasis.

The median age at death was 74.4 years for mild psoriasis and 72 years for severe psoriasis (76.5 years for controls).

Comorbidities (concomitant diseases)

  • Obesity (overweight)1+2
  • Arterial hypertension (high blood pressure)1+2
  • Arthritis (inflammation of the joints)1 – in children as juvenile arthritis (JIA); may precede psoriasis by months to years
  • Bronchial asthma (1.38 times more common).
  • Chronic inflammatory bowel disease (IBD), e.g. Crohn’s disease about two times more often.
  • Diabetes mellitus type 2 – average risk of diabetes of psoriasis-free patients 1.21 and psoriasis patients 1.64
  • Liver cirrhosis (irreversible damage to the liver leading to gradual connective tissue remodeling of the liver with impairment of liver function; 14.1% of all patients with severe psoriasis)
  • Metabolic changes such as hyperlipoproteinemias (dyslipidemia)1+2.
  • Psychiatric disorders1+2: As a result of skin appearance and social exclusion, anxiety disorders* , depression* as well as substance abuse* are significantly increased
  • Rheumatoid arthritis (about 4 times more often).
  • Celiac disease (4.1%); a gluten-free diet also shows beneficial effects on skin lesions

1Comorbidities in childhood2 Comorbidities independent of age.