Characteristics may vary according to the subtype of pustular psoriasis. For example, it can be localized, commonly to the hands and feet (localized pustular psoriasis), or generalized with widespread patches occurring randomly on any part of the body (generalized pustular psoriasis). However, all forms of pustular psoriasis share in common the presence of red and tender blotchy skin covered with pustules.

Pustular psoriasis can be localized, commonly to the hands and feet (palmoplantar pustulosis), or generalized with widespread patches occurring randomly on any part of the body. Acrodermatitis continua is a form of localized psoriasis limited to the fingers and toes that may spread to the hands and feet. Pustulosis palmaris et plantaris is another form of localized pustular psoriasis similar to acrodermatitis continua with pustules erupting from red, tender, scaly skin found on the palms of the hands and the soles of the feet.

Generalized pustular psoriasis (GPP) is also known as (von Zumbusch) acute generalized pustular psoriasis in acute cases, and as impetigo herpetiformis during pregnancy. GPP is a rare and severe form of psoriasis that may require hospitalization. This form of psoriasis is characterized by an acute onset of numerous pustules on top of tender red skin. This skin eruption is often accompanied by a fever, muscle aches, nausea, and an elevated white blood cell count. Annular pustular psoriasis (APP), a rare form of GPP, is the most common type seen during childhood. APP tends to occur in women more frequently than in men, and is usually less severe than other forms of generalized pustular psoriasis such as impetigo herpetiformis. This form of psoriasis is characterized by ring-shaped plaques with pustules around the edges and yellow crusting. APP most often affects the torso, neck, arms, and legs.

GPP presents as pustules and plaques over a wide area of the body. It differs from the localized form of pustular psoriasis in that patients are often febrile and systemically ill.

However, the most prominent symptom, as described in the "Archives of Dermatology", is “sheeted, pinhead-sized, sterile, sub-corneal pustules”. The IPC roundtable adds that these pustules often occur either at the edges “of expanding, intensely inflammatory plaques” or “within erythrodermic skin.”

Pustular psoriasis appears as raised bumps filled with noninfectious pus (pustules). The skin under and surrounding the pustules is red and tender.

Napkin psoriasis is a subtype of psoriasis common in infants characterized by red papules with silver scale in the diaper area that may extend to the torso or limbs. Napkin psoriasis is often misdiagnosed as napkin dermatitis (diaper rash).

Von Zumbusch psoriasis is named after the German dermatologist Leo Ritter von Zumbusch (1874–1940), son of Kaspar von Zumbusch who described the first documented case of generalized pustular psoriasis in the early 1900s. See Case Report #1.

Sometimes all or any of GPP is referred to as von Zumbusch psoriasis, but in the literature it is often distinguished as one specific form of GPP.

Eugene M. Farber, MD and colleagues provide a description of von Zumbusch psoriasis in "Pustular Psoriasis", published in "Cutis". They describe the pattern as having “waves of widespread or universally fiery redness”. The affected areas are “painful and tender”. Small sub-corneal pustules form, with sizes originally between 1 and 10 mm in diameter. These pustules may merge to form “yellow-green lakes of pus”. The pustules dry out, and “Waves of scarlatiniform [resembling scarlet fever] peeling follow, removing the desiccating pustules”. In regards to the onset, the von Zumbusch form may “supervene on any previous pattern of psoriasis”. It also may or may not recur periodically.

Pustular psoriasis is classified into two major forms: localized and generalized pustular psoriasis. Within these two categories there are several variants:

Erythroderma is generalized exfoliative dermatitis, which involves 90% or more of the patient's skin. The most common cause of erythroderma is exacerbation of an underlying skin disease, such as psoriasis, contact dermatitis, seborrheic dermatitis, lichen planus, pityriasis rubra pilaris or a drug reaction. Primary erythroderma is less frequent and is usually seen in cases of cutaneous T-cell lymphoma, in particular in Sézary's disease.

The most common causes of exfoliative dermatitis are best remembered by the mnemonic device ID-SCALP. The causes and their frequencies are as follows:

- Idiopathic - 30%

- Drug allergy - 28%

- Lymphoma and leukemia - 14%

- Atopic dermatitis - 10%

- Psoriasis - 8%

- Contact dermatitis - 3%

- Seborrheic dermatitis - 2%

Differential diagnosis in patients with erythroderma may be difficult.

Typically guttate psoriasis erupts after a throat infection, or strep throat. Initially, when the throat infection has cleared up, the person can feel fine for several weeks before noticing the appearance of red spots. They appear small at first, like a dry red spot which is slightly itchy. When scratched or picked the top layer of dry skin is removed, leaving dry, red skin beneath with white, dry areas marking where flakes of dry skin stop and start. In the weeks that follow the spots can grow to as much as an inch in diameter. Some of the larger ones may form a pale area in the center which is slightly yellow.

Guttate psoriasis can occur on any part of the body, particularly the legs, arms, torso, eyelids, back, bottom, bikini-line and neck. The number of lesions can range from 5 to over 100. Generally the parts of the body most affected are seen on the arms, legs, back and torso.

The classification of exfoliative dermatitis into Wilson-Brocq (chronic relapsing), Hebra or pityriasis rubra (progressive), and Savill (self-limited) types may have had historical value, but it currently lacks pathophysiologic or clinical utility.

Guttate psoriasis (also known as eruptive psoriasis) is a type of psoriasis that presents as small (0.5–1.5 cm in diameter) lesions over the upper trunk and proximal extremities; it is found frequently in young adults. The term "guttate" is used to describe the drop-like appearance of skin lesions. Guttate psoriasis is classically triggered by a bacterial infection, usually an upper respiratory tract infection.

Dyshidrosis has been described as having the following characteristics:

- Itchiness of the palms or soles, followed the a sudden development of intensely itchy small blisters on the sides of the fingers, the palms or the feet.

- These blisters are often described as having a "tapioca pudding" appearance.

- After a few weeks, the small blisters eventually disappear as the top layer of skin falls off.

- These eruptions do not occur elsewhere on the body.

- The eruptions may be symmetrical.

Although a clear understanding of the various skin lesions in IgG4-related disease is a work in progress, skin lesions have been classified into subtypes based on documented cases:

- Angiolymphoid hyperplasia with eosinophilia (or lesions that mimic it) and cutaneous pseudolymphoma

- Cutaneous plasmacytosis

- Eyelid swelling (as part of Mikulicz's disease)

- Psoriasis-like eruptions

- Unspecified maculopapular or erythematous eruptions

- Hypergammaglobulinemic purpura and urticarial vasculitis

- Impaired blood supply to fingers or toes, leading to Raynaud's phenomenon or gangrene

Note:

In addition, Wells syndrome has also been reported in a case of IgG4-related disease.

The most superficial obstruction (with the most mild clinical presentation), is known as "miliaria crystalline"; instead of a rash, the patient presents with multiple tiny blister-like lesions that look like beads of perspiration and essentially cause no symptoms. "Miliaria crystalline" is also known as "Miliaria crystallina," and "Sudamina". The superficial vesicles are not associated with an inflammatory reaction.

Neutrophilic dermatosis of the dorsal hands (also known as "Pustular vasculitis of the dorsal hands") is a skin condition that presents with edematous pustular or ulcerative nodules or plaques localized to the dorsal hands.

Symptoms of miliaria include small red rashes, called papules, which are irritated and itchy. These may simultaneously occur at a number of areas on a sufferer's body, the most common including the upper chest, neck, elbow creases, under the breasts and under the scrotum. Other areas include skin folds, areas of the body that may rub against clothing, such as the back, chest, and stomach, etc. A related and sometimes simultaneous condition is folliculitis, where hair follicles become plugged with foreign matter, resulting in inflammation.

The symptoms relating to miliaria should not be confused with shingles as they can be very similar. Shingles will restrict itself to one side of the body but also has a rash-like appearance. It is also accompanied by a prickling sensation and pain throughout the region. Those who suspect they have shingles and not miliaria should seek medical advice immediately as the sooner antivirals are taken, the better.

Psoriatic nails are characterized by a translucent discolouration in the nail bed that resembles a drop of oil beneath the nail plate. Early signs that may accompany the "oil drop" include thickening of the lateral edges of the nail bed with or without resultant flattening or concavity of the nail; separation of the nail from the underlying nail bed, often in thin streaks from the tip-edge to the cuticle; sharp peaked "roof-ridge" raised lines from cuticle to tip; or separation of superficial layers of the nail followed by loss of patches of these superficial layers, leaving thin red nails beneath; or nail pitting–punctate changes along the nail plate surface.

A papulosquamous disorder is a condition which presents with both papules and scales, or both scaly papules and plaques.

Examples include psoriasis, lichen planus, and pityriasis rosea.

Localized pustular psoriasis presents as two distinct conditions that must be considered separate from generalized psoriasis, and without systemic symptoms, these two distinct varieties being pustulosis palmaris et plantaris and acrodermatitis continua.

Psoriatic onychodystrophy or psoriatic nails is a nail disease. It is common in those suffering from psoriasis, with reported incidences varying from 10% to 78%. Elderly patients and those with psoriatic arthritis are more likely to have psoriatic nails.

Dyshidrosis, is a type of dermatitis, that is characterized by itchy blisters on the palms of the hands and bottoms of the feet. Blisters are generally one to two millimeters in size and heal over three weeks. However, they often recur. Redness is not usually present. Repeated attacks may result in fissures and skin thickening.

The cause is unknown. Triggers may include allergens, physical or mental stress, frequent hand washing, or metals. Diagnosis is typically based on what it looks like and the symptoms. Allergy testing and culture may be done to rule out other problems. Other conditions that produce similar symptoms include pustular psoriasis and scabies.

Avoiding triggers may be useful as may a barrier cream. Treatment is generally with steroid cream. High strength steroid creams may be required for the first week or two. Antihistamines may be used to help with the itch. If this is not effective steroid pills, tacrolimus, or psoralen plus ultraviolet A (PUVA) may be tried.

About 1 in 2,000 people are affected in Sweden. Males and females appear to be affected equally. It explains about one in five cases of hand dermatitis. The first description was in 1873. The name comes from the word "dyshidrotic," meaning "difficult sweating," as problems with sweating was once believed to be the cause.

Tetter refers to any skin condition characterized by reddish vesicular eruptions and intense itching. Common diseases called tetter include:

- Eczema and Duhring's disease

- Herpes

- Porphyria cutanea tarda (PCT)

- Psoriasis

- Ringworm and jock itch

Psoriatic erythroderma (also known as erythrodermic psoriasis) represents a generalized form of psoriasis that affects all body sites, including the face, hands, feet, nails, trunk, and extremities. First-line treatments for psoriatic erythroderma include immunosuppressive medications such as methotrexate, acitretin, or ciclosporin.

Eosinophilic pustular folliculitis of infancy (also known as "Eosinophilic pustular folliculitis in infancy," "Infantile eosinophilic pustular folliculitis," and "Neonatal eosinophilic pustular folliculitis") is a cutaneous condition characterized by recurrent pruritic crops of follicular vesiculopustular lesions.

Eosinophilic folliculitis associated with HIV infection typically affects individuals with advanced HIV and low T helper cell counts. It affects both men and women as well as children with HIV and is found throughout the world.

EF may also affect individuals with hematologic disease such as leukemia and lymphoma. It may also affect otherwise normal infants in a self-limited form. HIV-negative individuals can also develop EF — this is more common in Japan.

Dermatographic urticaria manifests as an allergic-like reaction, in general a warm red wheal (welt) to appear on the skin. It can often be confused with an allergic reaction to the object causing the scratch, when in fact it is the act of being scratched that causes a wheal to appear. These wheals are a subset of [urticaria] (hives) that appear within minutes, in some cases accompanied by itching. The first outbreak of urticaria can lead to others on body parts not directly stimulated, scraped, or scratched. In a normal case, the swelling will decrease with no treatment within 15–30 minutes, but, in extreme cases, itchy red welts may last anywhere from a few hours to days.