There are several main types of psoriasis, each presenting with different symptoms and characteristics. A psoriasis patient may present with more than one type, which may also change over time (National Psoriasis Foundation, 2019).
Plaque psoriasis (‘psoriasis vulgaris’) accounts for 90% of cases of psoriasis and is characterised by well-demarcated, infiltrated red plaques covered with a coarse silvery scaling.
Patients report itch, pain and bleeding and although the most commonly affected sites include elbows, knees, scalp, periumbilical and lumbar regions, plaque psoriasis can affect any area of the body including the nails (Nestle et al., 2009; Boehncke & Schön, 2015; National Psoriasis Foundation, 2019).
Find out from Professor Andrew Blauvelt the impact of affected body regions on treatment decisions.
Patients with guttate psoriasis will present with mostly small, red, scaly papules over the entire body surface, with the trunk being most commonly affected (National Psoriasis Foundation, 2019). This type of psoriasis is the most common type in children and young people below the age of 30, and may develop suddenly following a streptococcal throat infection or influenza (Boehncke & Boehncke, 2014; National Psoriasis Foundation, 2019).
Erythrodermic psoriasis (also called exfoliative psoriasis) is a rare form that is particularly inflammatory and frequently affects most of a person’s body surface. It generally appears on patients with unstable plaque psoriasis, affecting about 3% of people with psoriasis during their lifetime. It is characterised by widespread lesions that are not clearly defined and by shedding of large “sheets” of skin over a large area of the body. People with erythrodermic psoriasis frequently experience severe associated illness and have hypo- or hyperthermia, electrolyte disturbances, protein loss, dehydration, renal failure and cardiac abnormalities. Severe nail involvement is also characteristic (National Psoriasis Foundation, 2019).
Pustular psoriasis is a group of conditions which, as the name suggests, are characterised by the presence of white pustules surrounded by red skin. It typically affects adults and can be localised or more generalised across the body. The pustules are not a sign of infection, but are neutrophil filled and non-infectious (National Psoriasis Foundation, 2019; Twelves et al., 2018).
Psoriasis exclusively involving the palms and soles is known as palmoplantar psoriasis and can present as hyperkeratotic plaques or as pustules (Handa et al., 2010).
Find out why treatment for palmoplantar pustulosis is such an unmet need in psoriasis from Professor Ulrich Mrowietz.
The prevalence of nail involvement in psoriasis patients varies between 15% and 79%. The nail bed, nail matrix, hyponychium, and nail folds can be affected by nail psoriasis (Ventura et al., 2017). There is also a clear link with psoriatic arthritis; 80% of patients with nail symptoms will have psoriatic arthritis, compared with 50% with cutaneous symptoms alone (Williamson et al., 2004).
Nail psoriasis can be unsightly, may cause pain and functional disability, and is vulnerable to secondary infection. Nail signs of psoriasis include (Pasch, 2016; Ngan & Oakley 2016)