What is Psoriasis?

Psoriasis is a chronic inflammatory skin disease that causes itchy or sore patches of thick, red skin with silvery scales. Patients usually get the patches on various parts of the body such as elbows, knees, scalp, back, face, palms and feet. Psoriasis can be hard to diagnose because it appears similar to other skin diseases. A well-trained and qualified doctor can identify psoriasis and give better advice and treatment.

It can last for a long time, even for a lifetime in some severe cases. Symptoms can come and go but their effects stay forever. There are so many treatments are available to include creams, medicines and light therapy. It usually occurs in adults and runs in families sometimes. The most common locations of psoriasis are knees, scalp, and elbows but can appear on any part of the body.

Psoriasis triggers:

  • Infections

  • Stress

  • Dry skin

  • Certain medication

Who gets psoriasis?

In general, if we talk about the percentage of the population that is being affected by the psoriasis is 24% of males and females. It can be started at any age including childhood, even in the 50s and 60s. It tends to continue and exist lifelong, fluctuating in extent and severity. The main cause of psoriasis is hereditary or genetic. About one-third of the patients suffering from psoriasis have family members with psoriasis.

What causes psoriasis?

There are multi factors that cause psoriasis. There are some of the causes as follows:-

1. Genetic factors are important. Genetic profile of an individual’s influences their type of psoriasis and its response to treatment.

2. HLA-Cw6 is a major histocompatibility complex is associated with early onset and guttate psoriasis according to the study report of Genome-wide association and not associated with nail dystrophy, arthritis or late onset psoriasis.

3. Psoriasis is a result of a problem with your immune system. Cell turnover is a process when skin cells that grow deep in your skin rise to the surface. Generally, this process takes a month to complete but in psoriasis, it happens in few days because cells start rising too fast.

What are the clinical features of psoriasis?

1. Symmetrically distributed, red, scaly plaques with well-defined edges.

2. The scale is typically white not in skin folds where the scaly plaques often appear shiny and have a moist peeling surface.

3. Persistent without treatment.

4. Itchy and patients may feel discomfort that leads to scratching and lichenification (thickened leathery skin with increased skin markings)

5.  The occurrence of painful skin cracks or fissures.

6. Leave brown or pale marks after being cleared up after the treatment and marks can be expected to fade over several months.

How is psoriasis classified?

There are some certain features of psoriasis that can be categorized helps in determining appropriate investigations and treatment pathways. Overlapping may occur.

  • Below the 35 years – Early age of onset vs Above the 50 years

  • Acute in nature – Chronic Plaque Psoriasis vs Guttate Psoriasis

  • Localised - Palmoplantar psoriasis vs Generalised psoriasis

  • Small plaques = < 3 cm vs large plaques =  > 3 cm

  • Thick plaques vs thin plaques

  • Involvement of Nail vs No nail involvement

Types of psoriasis

Typical patterns of psoriasis are:

1. Post-streptococcal acute guttate psoriasis

  • Widespread small plaques

  • Often resolves after several months

2. Small plaque psoriasis

  • Often late age of onset

  • Plaques < 3 cm

3. Chronic plaque psoriasis

  • Persistent and treatment-resistant

  • Plaques >3 cm

  • Most often affects elbows, knees and lower back

  • Ranges from mild to very extensive

4. Unstable plaque psoriasis

  • Rapid extension of existing or new plaques

  • Koebner phenomenon: new plaques at sites of skin injury

  • Induced by infection, stress, drugs, or drug withdrawal

5. Flexural psoriasis

  • Affects body folds and genitals

  • Smooth, well-defined patches

  • Colonised by candida yeasts

6. Scalp psoriasis

  • Often the first or only site of psoriasis

7. Sebopsoriasis

  • Overlap of seborrhoeic dermatitis and psoriasis

  • Affects scalp, face, ears, and chest

  • Colonised by Malassezia

8. Palmoplantar psoriasis

  • Palms and/or soles

  • Keratoderma

  • Painful fissuring

9. Nail psoriasis

  • Pitting, onycholysis, yellowing, and ridging

  • Associated with inflammatory arthritis

10. Erythrodermic psoriasis (rare)

  • May or may not be preceded by another form of psoriasis

  • Acute and chronic forms

  • This type of psoriasis may result in systemic illness with temperature dysregulation, cardiac failure, and electrolyte imbalance.