Pemphigoid is a dermatological disease of unclear (presumably autoimmune) etiology with a chronic recurrent course, similar in its clinical manifestations to some forms of pemphigus. Symptoms of this condition include the appearance of rashes on the skin of the extremities, abdomen and chest, sometimes on the mucous membranes. The nature of the rash is tense blisters of various sizes (depending on the form of the disease). Diagnosis of pemphigoid is made on the basis of the results of examination of the skin, skin biopsy from the affected foci and histological examination of tissues, immunological studies. Corticosteroids, immunosuppressive agents and vitamin preparations are used to treat pemphigoid. Local therapy is carried out to prevent secondary infection.
Pemphigoid (non-antholytic pemphigus) is a chronic skin disease that is presumably autoimmune in nature, accompanied by the development of subepidermal tense blisters on the skin and mucous membranes. The forms of the disease have been described at different times, for example, conjunctival pemphigoid – in 1909, bullous pemphigoid – in 1953, a benign form developing in the oral cavity – in 1959. Dermatologists have revealed the main difference between pemphigoid and true pemphigus – the absence of real acanthosis and the development of blisters due to secondary immune processes in the dermis and epidermis.
Basically, this condition affects people over 50 years old, often occurs against the background of taking certain medications or oncological processes in the body. In some cases, it is possible to develop pemphigoid at a younger age, there are examples of this condition in children. It is not known for certain how often this pathology occurs among the population, especially with regard to the benign form of the disease, since many patients do not turn to a specialist because of the low severity of symptoms. Sometimes data is indicated in 3-30 cases per 1,000,000 people.
The lack of a clear position in the scientific community regarding the causes of pemphigoid leads to the development of numerous hypotheses about its supposed etiology. The vast majority of dermatologists agree that the main mechanism of skin tissue damage in this disease is autoimmune. This is confirmed by histological, immunological and biochemical studies, as well as the presence of positive dynamics in the treatment of pemphigoid with immunosuppressants. However, the causes of immunological disorders leading to this condition, for the most part remain unknown. For some forms of bullous pemphigoid, the relationship between individual alleles of the main histocompatibility complex (DQB1*0301) and the development of skin manifestations was revealed.
The pathogenesis of different forms of pemphigoid has many similar signs, various clinical manifestations of this condition are due only to the localization and severity of inflammatory processes. As mentioned above, the disease has an autoimmune nature and is caused by a pathological reaction of the immune system to the body’s own tissues. In the case of pemphigoid, proteins of the epidermis and its basement membrane become the object of attack of the immune system – for example, in the bullous form of the disease, these are proteins BP180 and BP230. A similar mechanism of development is observed in scarring and benign types of pathology, but specific autoantigens have not yet been identified. A reaction to a complex of various protein factors is assumed. Ultraviolet radiation, taking certain medications, immune disorders, endocrine disorders and other circumstances can act as triggers of pemphigoid.
The initial symptoms of pemphigoid occur when a special clone of T-lymphocytes appears in the body, which has sensitivity to its own skin tissues or mucous membranes. T-lymphocytes are able to activate other links of the immune response with the participation of B-lymphocytes and plasmocytes producing antibodies (mainly of class M and G), also directed against epidermal proteins. Basically, the proteins of the semidesmosomes are attacked – special structures that ensure the interaction of cells within the epidermal layer. Their destruction leads to the development of the main symptoms of pemphigoid – the formation of first subepidermal and then intraepidermal blisters due to the violation of intercellular relationships. An allergic factor also plays a role in the development of any form of pemphigoid – histological studies reveal a significant number of labrocytes in the foci of skin lesions, in many cases the symptoms of the disease weaken when taking antihistamines.
Classification and symptoms
Almost immediately after the isolation of pemphigoid into a separate nosological unit, the disease was divided into several clinical forms with common etiology and pathogenesis, but different course and prognosis. The reasons why the patient has this, and not another form of the disease have not been reliably established. Perhaps the level of reactivity of the body plays a role, some experts believe that the reason for this lies in various autoantigens of the skin or mucous membranes. An indirect confirmation of the latter opinion can be the fact that in dermatological practice there are no cases of transition from one form of pemphigoid to another. There are the following types of the disease:
- Bullous pemphigoid (Lever’s pemphigoid, classical non–antholytic pemphigus) is the most common and most severe form of the disease, most often develops in people over 60 years of age, mainly in men. At first (pre-bubble stage), redness, moderate itching, and sometimes minor rashes appear on the surface of the skin of the abdomen, chest, back and limbs of patients. Then, in the above–mentioned areas of the body, tense bubbles of 1-3 centimeters in size, hemispherical in shape, filled with serous (occasionally hemorrhagic) exudate are formed. The location of the blisters and their accompanying urticary eruptions has a symmetrical character relative to the median line of the body. With a severe course of bullous pemphigoid, general symptoms may occur (fever, weakness, weight loss), in some cases, a fatal outcome is possible. The course of the disease is long with frequent relapses and exacerbations.
- Scarring pemphigoid (mucosinechial bullous dermatitis, pemphigus of the eyes) – this type of disease mainly affects the mucous membranes, in extremely rare cases, skin rashes may occur. Pathology is usually diagnosed in people aged 35-50 years, about three times more often occurs in women than in men. On the mucous membrane of the oral cavity with this type of pemphigoid, bubbles are formed from 5 millimeters to 1.5 centimeters in size, filled with serous contents. If the lid of the bubble is damaged, an erosive surface appears in its place, which, as a rule, does not bleed and does not tend to grow. After the erosion heals, atrophic scars remain. The scarring pemphigoid of the conjunctiva of the eye has its own characteristics – almost immediately after the appearance of the first signs of the disease, adhesions form between the conjunctiva and the mucous membrane of the eyelid. With a prolonged course of the disease, these adhesions become more and more, which can lead to blindness.
- Benign pemphigoid is the most favorable prognostic form of the disease. Bubbles occur exclusively on the surface of the oral mucosa, are up to one centimeter in size, and are painless. After their damage, erosive surfaces remain, which heal without a trace within 1-2 weeks. Benign mucosal pemphigoid is characterized by a chronic course with a tendency to spontaneous disappearance of symptoms. In extremely rare cases, this condition can be complicated by a secondary infection.
To determine one or another form of pemphigoid, dermatological examination, histological examination of skin tissues in the affected area, study of the patient’s medical history and immunochemical studies are used. Additional consultations with an ophthalmologist or dentist may be required. Upon examination, depending on the shape of the pemphigoid, the presence of blisters on the skin of the trunk, the mucous membranes of the oral cavity or the conjunctiva of the eyes is revealed, urticary rashes and areas of eroded skin can also be determined.
Histological examination reveals a sharp edema of the dermis and lymphocytic infiltration with an admixture of neutrophils and labrocytes. Depending on the stage of the rash, a subepidermal gap may be observed, then turning into a subepidermal vesicle, which after a while transforms into an intraepidermal vesicle due to partial regeneration of the epithelium at the basement membrane. Immunofluorescence in various forms of pemphigoid confirms the accumulation of immunoglobulins G and M at the basement membrane or submucosal plate.
Due to the unexplained etiology of pemphigoid, there is no specific treatment for this condition in dermatology. General and local forms of glucocorticoids are used to relieve symptoms. Especially high doses of these drugs are necessary for the scarring form of the disease with conjunctival lesions. In addition, immunosuppressive agents, cytostatic drugs and some antibiotics are used in the course of pemphigoid therapy.
Drug treatment of this condition is often difficult due to the advanced age of patients and the presence of concomitant diseases that limit the appointment of such serious drugs with possible side effects. Antiseptics (chlorhexidine, aniline dyes) are used locally to prevent secondary infection. Treatment of any form of pemphigoid is a long process, often taking many months (up to a year and a half).
Prognosis and prevention
The prognosis of pemphingoid depends on the clinical form of pathology and the severity of the symptoms of the disease. The bullous variety of this condition in some cases (especially when the body is weakened or depleted) can lead to a fatal outcome, however, many data on high mortality, sometimes reaching 30-40%, cannot be considered correct, since they do not take into account additional factors (age of patients, concomitant pathologies). The scarring form of pemphigoid is dangerous when developing on the conjunctiva of the eye, since without specialized treatment it can cause blindness. In contrast, benign pemphigoid, even with a long-term chronic course, usually does not lead to serious complications. Patients with this dermatological pathology should avoid high doses of UV, mechanical damage to the skin and burns.