Pyoderma gangrenosum is a secondary dermatosis with destruction of the skin and necrosis of the underlying tissues, accompanying systemic pathologies. Clinically manifested by a rash of bullae with serous, purulent or hemorrhagic contents, which are opened, forming pink palm-sized ulcers expanding along the periphery with torn edges and pyogenic discharge. The appearance of ulcers is accompanied by a prodroma. Pyoderma gangrenosum is diagnosed on the basis of a history of systemic pathology and typical skin symptoms – pyogenic ulcers. To exclude other dermatoses, a complex of laboratory tests is performed. Primary pathology is treated, corticosteroids and antibiotics are prescribed inside in parallel, turbulent baths and wet antiseptic dressings are applied externally.
Pyoderma gangrenosum is a severe progressive necrosis of the skin that occurs against the background of systemic pathology and is characterized by the formation of deep ulcers with purulent-necrotic discharge. Pyoderma gangrenosum is a rare disease, diagnosed annually in 1-3 out of 100,000 people. Most often, skin pathology accompanies inflammatory diseases of the digestive system (30%), patergia (30%), arthritis, tumors, leukemia. From 25% to 50% of cases of pyoderma gangrenosum are idiopathic. The first descriptions of gangrenous phagedenic ulcers belong to the French dermatologist Louis Brock, who studied this pathology at the beginning of the twentieth century. The modern idea of nosology was introduced into dermatology by American specialists A. Bransting, V. Hockerman and P. O’Leary in 1930.
Pyoderma gangrenosum has other names: geometric phagedenism, ulcerative dermatitis, serpinginating and gangrenous-ulcerative vegetative pyoderma. The essence of the names of pathology is associated with the main clinical symptom of the disease – a progressive purulent necrotic ulcer. The phagedenic form of the disease occurs exclusively in tropical and subtropical countries of both hemispheres, where the climate is damp and hot. Other forms are non-endemic. The pathological process occurs at any age, the peak incidence occurs at 20-40 years, children rarely get sick. There is a slight predominance of female patients. The urgency of the problem is associated with serious trophic disorders, which significantly reduce the quality of life of patients.
The etiology and pathogenesis of the pathological process are not precisely established. In some cases, hereditary predisposition matters. Pyoderma gangrenosum as a symptom complex is part of the rare genetically determined syndromes PAPA (purulent arthritis, v, gangrenous acne), PASH (pyoderma gangrenosum, acne, purulent hydradenitis) and PASS (purulent arthritis, pyoderma gangrenosum, acne, purulent hydradenitis). The cause of these syndromes are mutations of the PSTPI1/CD2BP1 gene located on chromosome 15q. Pathologies are inherited by an autosomal dominant mechanism.
There is also an immune theory of the development of pyoderma gangrenosum. According to this theory, the pathological process occurs against the background of altered sensitivity of the dermis to endogenous and exogenous agents. Long-term chronic somatic diseases cause changes in cellular and humoral immunity due to violations of neuroendocrine regulation, metabolic processes, tissue trophic. An aberrant immune reaction begins, in which T-lymphocytes and cytokines are involved. T helper cells of the immune system produce antibodies – reagins that create the basis for skin sensitization. At the same time, T-suppressors try to suppress these reactions, as a result, a non-standard immune response develops in the form of necrotic destruction of connective tissue.
The process of ulcer formation in pyoderma gangrenosum goes through three stages. At the stage of immune reactions, there is an accumulation of antibodies specific to a certain type of antigen. At the same time, immune lymphocytes and class E antibodies from the blood pass into the skin tissue, sensitizing it. At the second (pathochemical) stage of the disease, repeated ingestion of a foreign antigen causes activation of proteolytic enzymes of cells and tissues with a violation of their functions. Epidermal cells begin to produce biologically active substances that provoke inflammation. At the third (pathophysiological) stage, there is a specific skin response to the introduction of a pathological antigen in the form of cell degranulation, vascular destruction, trophic disorders and local tissue destruction. The depth of destruction depends on the amount of pathogenic antigen and the degree of resistance of the immune system.
In modern dermatology, it is customary to distinguish several varieties of the pathological process. Allocate:
- Classical (ulcerative) pyoderma gangrenosum, which is characterized by deep purple-tinged ulcers with edges hanging over the surface of the skin defect. Pathology is combined with systemic processes in the intestines, joints, and lung tissue. This group includes pyostomatitis, pyogenic gangrenous lesion of the genitals, periorbital tissues, and mucous membranes of the upper respiratory tract.
- Atypical pyoderma gangrenosum, consisting of bullous and pustular varieties. This form of the disease is accompanied by blast leukemia or myeloproliferative diseases, characterized by vesicular or pustular rashes on the edematous border along the periphery of the ulcer with localization on the face and extremities.
- Posttraumatic pyoderma gangrenosum that occurs against the background of patergia.
- Phagedenic pyoderma gangrenosum, endemic to the tropics and subtropics, the distinguishing feature of which is multiplicity and strong adhesion with the underlying tissues.
- Malignant superficial granulomatous pyoderma gangrenosum accompanying systemic pathologies and malignant tumors.
Changes on the surface of the dermis are debuted by furuncle-like elements with transparent or hemorrhagic contents against the background of hyperemia. The surface of the skin in the places of rashes with pyoderma gangrenosum infiltrates, then necrotizes with the formation of a polycyclic ulcer increasing in depth and breadth, reaching the size of the palm of an adult. At the peak of its development, the lesion is a continuous ulcerative surface with roller-like edges and frills from the remnants of the epidermis. A livid ulcer with raised edges and a wide band of hyperemia around the perimeter is filled with pus, blood clots, remnants of the epidermis and bacteria, exudes a stench. The bottom of the skin defect is bumpy, covered with bright granulations. The outcome of pyoderma gangrenosum is reepithelization from the edges of the defect into the scar.
The subjective state is little disturbed, the formation of ulcers is accompanied by soreness, prodromal phenomena appear during exacerbations, arthralgias, myalgias join. Pyoderma gangrenosum begins acutely, but is chronicled fairly quickly, has a wave-like course with frequent relapses. In 50% of the localization of the pathological process is the shin, as a rule, the focus is single. Phagedenic ulcers are more often multiple, occur mainly on the genitals. A distinctive feature of this form of pyoderma gangrenosum is the rapid formation of an ulcer covered with a gray diphteroid coating and tightly soldered to the underlying tissues. The roller around the skin defect has pointed edges and an extremely dense consistency. The formation of a tissue defect is accompanied by polyneuritis and lymphangoitis.
The clinical diagnosis is made by a dermatologist on the basis of anamnesis, specific symptoms and consultations of narrow specialists, since pyoderma gangrenosum is an interdisciplinary disease. The histology of the lesion is not indicative, but in difficult cases it is useful. Vascular thrombosis, granulomatous infiltrates, islets of destruction in the epidermis and dermis are detected. Additionally, serum protein electrophoresis is performed, the mycotic nature of the ulcer is excluded, blood is taken for RW. Pyoderma gangrenosum is differentiated with ulcerative tuberculosis of the skin, tertiary syphilis, deep dermatomycosis, vegetative ulcerative pyoderma, carbuncle, Wegener’s granulomatosis, panniculitis, amoebiasis, bromoderma, gangrene, vegetative pemphigus, mycobacterial and clostridial infection, trophic disorders, pustular psoriasis.
The therapy of pyoderma gangrenosum begins with the correction of somatic pathology in specialized specialists, since the skin pathological process is poorly amenable to therapy without this. The purpose of dermatological treatment is the removal of inflammatory manifestations, painful sensations, restoration of the skin. To do this, hormone therapy and antibiotic therapy courses are conducted. In severe cases, cytostatics, immunosuppressants, potassium iodide are connected, and immunoglobulin is injected intravenously. Plasmapheresis is shown. Externally, with pyoderma gangrenosum, the surface of the skin defect is cleaned using vibration-turbulent baths, antiseptic solutions. Wet-drying bandages with silver solutions, hormonal preparations are used. Taking into account patergia, they try to avoid surgical manipulations. The prognosis of pyoderma gangrenosum is determined by the primary pathology that caused the ulcer.