Table 1 The feature of different types of psoriasis [3,4,5,6]

Plaque psoriasis

Sharply circumscribed, round-oval, or nummular (coin-sized) plaques. The lesions may initially begin as erythematous macules (flat and 1 cm) or papules, extend peripherally, and coalesce to form plaques of one to several centimeters in diameter. A white blanching ring, known as Woronoff‘s ring, may be observed in the skin surrounding a psoriatic plaque.

Guttate psoriasis

Acute onset of a myriad of small, 2–10 mm diameter lesions of psoriasis. These are usually distributed in a centripetal fashion, it can also involve the head and limbs. Classically, it occurs shortly after an acute β-haemolytic streptococcal infection of the pharynx or tonsils and can be the presenting episode of psoriasis in children or adults occasionally.

Pustular psoriasis

Multiple tender sterile pustules with an underlying, blotchy, erythematous base. The patient may be pyrexial.

Erythrodermic psoriasis

Generalized erythema involving the majority of the body surface area. It may be a manifestation of unstable psoriasis precipitated by infection, tar, drugs, or withdrawal of corticosteroids.