Microbial eczema is a clinical type of eczema that has a secondary character and develops in areas of microbial or fungal skin lesions. The disease is characterized by the addition of inflammatory changes characteristic of eczema to the symptoms of an existing background disease. The diagnosis is aimed at identifying the pathogen by back-seeding the separated eczema elements or scraping on pathogenic fungi. Treatment includes therapy of the existing disease, the use of antimicrobials, general and local treatment of eczema.
L30.3 Infectious dermatitis
According to various authors, microbial eczema accounts for 12% to 27% of all cases of eczema. It develops in places of chronically occurring pyoderma: around trophic ulcers, poorly healing postoperative or post-traumatic wounds, fistulas, abrasions. Disease can occur in areas of varicose veins and lymphostasis, as well as with long-term fungal skin diseases.
The most common pathogen detected in microbial eczema is beta-hemolytic streptococcus. However, the development of microbial eczema may be associated with epidermal or Staphylococcus aureus, proteus, klebsiella, neisseria gonorrhea or meningitis, Candida fungi and other pathogens. Background disease (varicose veins, lymphedema) significantly reduces the barrier function of the skin, and chronic exposure to microbial agents causes sensitization of the body and the occurrence of autoimmune reactions. Together, these processes lead to the development of microbial eczema.
The area of skin lesion in microbial eczema is most often located in the lower extremities. It represents large foci of acute inflammatory skin changes with serous and purulent papules, vesicles (vesicles), wet erosions located on them. The foci are characterized by coarse-grained edges. They merge with each other and do not have healthy skin areas separating them. Rashes are usually accompanied by significant itching. Inflammatory foci of this disease are covered with a large number of purulent crusts. They tend to grow peripherally and are surrounded by a section of the rejected stratum corneum. On apparently healthy skin around the lesion area, individual pustules or foci of peeling are observed — screening of microbial eczema.
Clinical dermatology distinguishes several types of microbial eczema: nummular, varicose, posttraumatic, sycosiform and nipple eczema.
- Coin-shaped eczema (nummular or plaque) is characterized by rounded lesions of 1-3 cm in size with clear edges, a hyperemic and edematous wet surface covered with layers of serous-purulent crusts. The usual localization of monetoid eczema is the skin of the upper extremities.
- Varicose microbial eczema develops with varicose veins with the phenomena of chronic venous insufficiency. Factors contributing to the occurrence of microbial eczema may be infection of a trophic ulcer, traumatization of the skin in the area of varicose veins or its maceration during dressings. This form of the disease is characterized by polymorphism of elements, clear boundaries of the focus of inflammation and moderate itching.
- Post-traumatic eczema develops around areas of injury to the skin (wounds, abrasions, scratches). It may be associated with a decrease in the protective reactions of the body and a slowdown in the healing processes.
- Sycosiform microbial eczema in some cases may develop in patients with sycosis. This type is characterized by wet and itchy foci of red color, having a typical localization for sycosis: beard, upper lip, armpits, pubic area. At the same time, the inflammatory process often goes beyond the boundaries of hair loss.
- Eczema of the nipples occurs in women with frequent injury of the nipples during breastfeeding or with their constant combing in patients with scabies. Bright clearly delimited foci of red color with wetness and cracks are formed in the area of the nipples. Their surface is covered with crusts. There is a strong itching. Eczema of the nipples, as a rule, is characterized by a persistent course of the process.
Inadequate therapy or traumatic effects on lesions can lead to the appearance of secondary allergic rashes. Such rashes differ in polymorphism and are represented by red-edematous spots, vesicles, pustules and papules. With the progression of the process, these rashes merge, forming areas of wet erosions, and spread to previously healthy areas of the skin. Thus, microbial eczema is transformed into true eczema.
The secondary nature of eczema, its development against the background of varicose veins, streptodermia, candidiasis, areas of infection or injury to the skin allow the dermatologist to assume microbial eczema. To determine the pathogen and its sensitivity to antibacterial therapy, bacteriological seeding of the separated or scraped skin lesion is carried out. If the fungal nature of the infection is suspected, a scrape is taken on pathogenic fungi.
In difficult diagnostic situations, a histological examination of a biopsy taken from the focus of microbial eczema can be carried out. The study of the drug determines edema of the dermis, spongiosis, acanthosis, the formation of blisters in the epidermis, pronounced lymphoid infiltration with the presence of plasmocytes. Differential diagnosis of microbial eczema is carried out with other types of eczema, psoriasis, dermatitis, primary skin reticulosis, benign familial pemphigus, etc.
In the case of microbial eczema, treatment is primarily aimed at eliminating the focus of chronic infection and treating the background disease. Depending on the etiology of the disease, course and local treatment of fungal skin diseases, a course of drug treatment and treatment of affected skin areas with pyoderma, treatment of trophic ulcers or sycosis are carried out.
Antihistamines and desensitizing medications (mebhydroline, chloropyramine, loratadine, desloratadine), B vitamins, sedatives are used in the treatment of microbial eczema. Local therapy includes the use of antibacterial or antifungal ointments, astringents and anti-inflammatory agents, antiseptics.
Among the physiotherapeutic methods of treatment for microbial eczema, magnetotherapy, UFO, UHF, ozone therapy and laser therapy are used. Patients should switch to a hypoallergenic diet, carefully observe personal hygiene, and avoid injury to the foci of microbial eczema. With the dissemination of the process and its transition to true eczema, a course of glucocorticoid therapy is prescribed.
Prognosis and prevention
The prognosis of microbial eczema with adequate treatment is favorable. A prolonged and persistent course of eczema can be observed in weakened patients and the elderly. In the prevention of microbial eczema, the main importance is the identification and treatment of those diseases against which it can develop, the prevention of infection of wounds, compliance with hygiene rules.