Types of psoriasis – what are they and how do they manifest?

Psoriasis can be classified according to several criteria – the most common classification divides psoriasis into:

• acute (including subacute form)
• chronic

Psoriasis is also classified according to the location of occurrence. It can occur:

• in body folds (psoriasis inversa)
• in the scalp (psoriasis capillitii)
• on the nails (psoriasis unguium)
• on the palms and soles (psoriasis palmoplantaris)

In clinical practice, we also encounter the so-called special forms of psoriasis, including:

• plaque psoriasis (psoriasis vulgaris)
• pustular psoriasis (psoriasis pustulosa)
• guttate psoriasis (psoriasis guttata)
• erythrodermic psoriasis (psoriasis erythrodermica)

In the following lines, we will mention selected and most common types of psoriasis.

This is the most common form of psoriasis, affecting approximately 85-90% of patients with psoriasis. Lesions commonly occur on elbows, knees, the scalp, and the lower back.

Typical are sharply demarcated red-pink lesions covered with silvery scales. Doctors use indices (PASI, BSA, DLQI) to assess the severity of the condition. According to this, psoriasis is classified as:

• mild,
• moderate,
• severe.

This is a distinct form of psoriasis characterized by the presence of pustules, or blister-like lesions filled with pus. It can occur in various forms:

• generalized pustular psoriasis (von Zumbusch)
• palmoplantar pustulosis
• acrodermatitis continua suppurativa (acro-pustulosis)
• impetigo herpetiformis (during pregnancy)

This is commonly an acute form of psoriasis. It typically occurs in younger patients after overcoming an acute infection (mostly streptococcal tonsillitis). It manifests as numerous smaller lesions the size of droplets, densely scattered across the entire body. Itching often accompanies the outbreak.

Psoriatic erythroderma is a condition where psoriatic manifestations spread to the entire surface of the skin. The skin is intensely red and may be covered with scales. Additionally, lymph nodes may be enlarged, and there may be increased body temperature, joint pain, and significant itching.

Patients also have a higher risk of developing infections and heart failure.

The characteristic feature of this form of psoriasis is the atypical localization of skin manifestations. They concentrate in areas of skin folds and are accompanied by significant itching.

This is psoriasis affecting the scalp, occurring at the border between hair and non-hairy skin, mainly above the forehead and in the temple area. In some cases, the condition can affect the entire scalp (the part of the head covered with hair). Lesions are covered with significant layers of scales.

Scalp psoriasis often occurs with other types of psoriasis, and it is important to differentiate it from seborrheic dermatitis during the initial diagnosis.

Nail psoriasis occurs either as part of the cutaneous form of psoriasis or independently (in 5-10% of cases). It occurs in up to 70% of patients with psoriatic arthritis.

Nails are typically affected symmetrically, with numerous small indentations on the nail plates. Thickened nails with ridges and without shine develop when the nail matrix is affected, a condition referred to as nail dystrophy. Psoriatic lesions in the nail bed alter the nail color and resemble oil spots.

In this case, it may be a standalone condition localized only on the palms and soles, or it may be a manifestation within the scope of plaque psoriasis. Palmoplantar psoriasis is often resistant to treatment..

The aforementioned types of psoriasis affecting the skin often spread to the joints, a condition known as psoriatic arthritis. This type of psoriasis mainly affects the small joints of the hands (including surrounding tissues) and the spine. The joints are asymmetrically affected, painful, swollen, and the skin over them appears red.

Psoriatic arthritis mainly occurs in people aged 30 to 50 years, and its treatment falls under the purview of a rheumatologist.