Pustular psoriasis is the most severe exudative rarely occurring form of psoriasis that threatens the patient’s life during the generalization of the process. It is characterized by hyperemia, against the background of which bullous serous-purulent elements appear, which tend to merge, open, form erosions, dry up with the outcome into crusts and the addition of secondary infection. Diagnosis is carried out on the basis of anamnesis, clinic, diagnostic triad (stearin stain, terminal film, drip bleeding), Kebner’s symptom, skin biopsy. Treatment is carried out according to individual schemes.
Pustular psoriasis is a type of non–infectious contact allergic dermatitis induced by inadequate therapy. The disease belongs to the category of incurable, has a systemic character, is represented by dermatoses of the first type associated with the HLA-antigen system and the second, unrelated to HLA-antigens – histocompatibility leukocyte antigens unique for each person. According to statistics, about 3% of dermatological patients suffer from pustular psoriasis. The pathological process has no gender component, it develops in women at the age of 16 and earlier, and in men it debuts after 22 years. Pustular psoriasis does not have pronounced racial and seasonal differences, but in countries with hot climates and among representatives of the Negroid race it is somewhat less common. For the first time, “purulent psoriasis” was described by the German dermatologist Zumbusch in 1909. The relevance of the topic is determined by the possibility of a fatal outcome and an increase in the incidence of this pathology.
The pathological process is heterogeneous. The exact cause of pustular psoriasis is unknown. An important role in its development belongs to hereditary predisposition, malfunctions of the immune, digestive and endocrine systems, as well as stress, allergic sensitization of the body, infections and skin injuries. In 60%, the trigger of the pathological process is irrational therapy, both of psoriasis itself and its accompanying diseases. In 40%, pustular psoriasis occurs spontaneously, against the background of visible well-being.
The mechanism of development of the pathological process in both variants is a violation of the normal functioning of the cells of the epidermis. With transdermal penetration of a pathogenic allergen, an immune malfunction occurs at the cellular-humoral level. Against the background of congenital instability of lysosomes, lysosomal cell membranes are damaged, in response, the synthesis of cytokines, inflammatory mediators begins.
In parallel, antibody-producing T-lymphocytes are activated. They enter into autoimmune reactions with their own epidermis, increasing inflammation and proliferative processes. The cell cycle is shortened, the process of differentiation of epidermal cells is disrupted. Hyperproliferation aggressively increases inflammation, epidermal cells begin to produce interleukin, which together with activated T-lymphocytes promotes even greater cell division. This is how the chronization of pustular psoriasis occurs.
The development of pathology against the background of visible health is interpreted as a failure of the metabolic processes of the body. Triggers can be transferred infections, bad habits, stress. In this case, there is an imbalance of tissue homeostasis, leading to a violation of proliferative activity and differentiation of epidermal cells. Due to metabolic disorders, keylons (tissue hormones of local immunity of protein nature) cease to inhibit proliferation in the upper layers of the skin, creating a disparity between secondary messengers, increasing the amount of cGMP (cyclic guanosine monophosphate – a derivative of guanosine triphosphate) and decreasing – cAMP (cyclic adenosine monophosphate – an ATP derivative). As a result, proliferative processes are stimulated with impaired differentiation of epidermal cells. Visually, this is manifested by the appearance of pustules.
There is no single classification of pustular psoriasis. At the same time, all modern dermatologists distinguish several stages of the development of the disease: initial or progressive (pustules spreading over the entire surface of the skin, prone to fusion, a positive symptom of Kebner), stationary (the spread of pustules is over, a pseudoatrophic Voronov rim appears – a sign of the transition to regression, the phenomenon of Kebner is negative), attenuating, regressive (plaques become flat, flesh-colored, without scales, limited by the horn belt, the focus regresses from the central part).
There is a division of pathology by severity: mild (the area of the lesion is limited, there are no symptoms of intoxication, inflammation is weakly expressed, the subjective state is not disturbed), medium (the process tends to spread, symptoms of prodroma appear against the background of exacerbation of concomitant pathology, inflammation is pronounced), severe (total skin damage, symptoms of intoxication and inflammation are pronounced, a secondary infection joins, somatic pathology progresses, the process becomes systemic, a fatal outcome is possible). The most common division of pustular psoriasis into two large groups: generalized and local forms.
Generalized forms (generalized pustular psoriasis) occur suddenly, in the midst of complete visible well-being or against the background of already existing concomitant diseases (actually pustular psoriasis), occupy more than 10% of the skin surface, are characterized by the formation of erythema with pustules in combination with itching and burning of the skin. Many authors, taking into account the single primary element of the rash (pustules), include three components in generalized dermatosis: Tsumbush pustulosis, Allopo acrodermatitis (typical form) and herpetiform impetigo of pregnant women. But most modern dermatologists consider all three components as independent diseases with their own etiology and mechanism of development, and refer to generalized forms of dermatosis:
- Tsumbusha pustulosis, characterized by the acute onset of a rash of pustules with prodroma, itching and burning of the skin.
- Drug-induced pustulosis, which occurs with incorrect treatment of common vulgar psoriasis.
- Subcorneal Sneddon-Wilkinson pustulosis, characterized by a rash on the skin of the trunk and extremities of pustules with a rim of hyperemia along the perimeter.
- Anular pustulosis, accompanied by the formation of pustular foci of the type of annular centrifugal erythema and proceeding without violations of the general condition.
- Generalized psoriasis pustulosis, characterized by attacks of rash of painful pustules prone to grouping, is included in this group because of the mechanism of occurrence identical to herpetiform impetigo of pregnant women.
- Juvenile pustulosis, occurs only in children, flows gently, spontaneously resolves itself.
Localized forms occupy up to 10% of the surface of the skin, are located in strictly defined places, flow softer than generalized ones. Some authors tend to include Barber’s palmar-plantar pustulosis and the atypical form of acrodermatitis Allopo, however, most specialists in the field of dermatology consider these types of disease as varieties of separate independent nosologies and refer to the local form of pustular psoriasis the following options:
- Pustulosis of skin folds – occurs in patients with endocrine pathology, papules form macerated foci with the addition of coccal infection.
- Palmoplantar pustulosis – pustules form foci on the shins and forearms.
- Andrews pustular bacterid – as a result of the influence of focal foci of infection, pustules arise spontaneously, affect the palms and soles. The disease refers to pustular psoriasis due to the identical mechanism of development according to the immune scenario.
Symptoms and diagnosis
The pustular psoriatic process has clinical manifestations common to all varieties, is characterized by the formation of itchy erythema, somewhat rising above the surrounding skin, with serous-purulent bulls that tend to spread, grouping, merging. A little later, the pustular foci begin to peel off, the scales separate, exposing the erosive surface, lymph nodes, nails, joints are involved in the pathological process. Localization corresponds to the form of pustular psoriasis. In severe cases, the general well-being of the patient is disturbed, concomitant pathology worsens, symptoms of intoxication increase up to a fatal outcome.
The clinical diagnosis is made by a dermatologist based on anamnesis, manifestations, diagnostic triad (a symptom of a stearin stain, a terminal film with protruding blood “dew drops”), a complete clinical and laboratory examination, including a blood test for rheumatoid factor and antibodies to HIV, histology, sterility culture, radiography for arthritis. Differential diagnosis is carried out with papular syphilis, seborrheic manifestations, lichen planus, parapsoriasis, atopic dermatitis.
Treatment and prognosis
The pathological process is stopped under the supervision of a dermatologist according to an individual scheme for each patient. They begin with the external treatment of pustular psoriasis, the purpose of therapy is to soften and cleanse the skin. In parallel, concomitant pathology is corrected, sedatives, antihistamines, vitamin therapy are connected. Generalization of the process requires hospitalization and the use of systemic drugs inside and by injection. A good effect is given by UVI, PUVA therapy of psoriasis, X-rays, cryotherapy.
As a preventive measure, dispensary observation with preventive treatment according to indications, sanatorium-resort rehabilitation, diet therapy is mandatory. With timely adequate treatment, the prognosis is relatively favorable, in the absence of therapy, in some cases, a fatal outcome is possible.