Generality
Bullous pemphigoid is an autoimmune disease characterized by the appearance of blisters on the skin .
This skin disorder is supported by the presence of auto-antibodies mistakenly directed against the epidermis basement membrane . The result of this interaction is the detachment of the latter from the underlying dermis, from which the bullous eruption follows.
Bubbles of bullous pemphigoid are broad and tense (ie fixed and not flaccid), with a clear content, and are accompanied by severe itching ; often, these lesions can occur on normal-looking skin or on the edge of erythematous plaques. The involvement of the mucous membranes is, however, rather rare.
Bullous pemphigoid has a relatively benign chronic course, with periods of spontaneous remissions alternating with recurrences. Only in some cases, the disease correlates to an unfavorable prognosis, leading the patient to death.
Diagnosis is established based on the clinical presentation and skin biopsy, supported by the immunofluorescence of the skin and serum.
The treatment of choice of bullous pemphigoid involves the use of systemic and topical corticosteroids . Most patients require long-term maintenance therapy, for which a variety of immunosuppressants can be used.
What's this
Bullous pemphigoid is a chronic autoimmune disorder that causes blisters to appear on normal or erythematous-looking skin. These serous or serum-hematic lesions cause intense itching.
Bullous pemphigoid is immunologically characterized by the presence of autoantibodies mistakenly directed against two healthy and normal structural proteins of the body, which are interpreted as dangerous antigens, therefore considered worthy of an immune attack.
Causes and Risk Factors
Bullous pemphigoid is the most common form of autoimmune bullous dermatosis . The disease affects mainly in old age.
Pemphigoid Bolloso: what are the causes?
Bullous pemphigoid is characterized by the presence of IgG auto-antibodies directed towards antigens (represented by two structural proteins, called BPAg1 and BPAg2 ) present in the basement membrane, ie the structure that separates the epidermis from the underlying dermis.
This interaction causes the formation of blisters through a complex mechanism:
- Once triggered, the autoimmune reaction causes the release of a series of proteolytic enzymes at the level of hemidesmosomes (ie in the areas of adhesion of the basement membrane);
- Proteolytic enzymes cause the detachment of the junctional bridges between the cells at the level of the most superficial portion (shiny lamina);
- The consequence is tissue damage which results in blistering and blistering.
Triggering or aggravating factors
- Bullous pemphigoid predominantly affects older people, but the disease has also been described in children.
- As with other autoimmune diseases, the exact factors that trigger or exacerbate bullous pemphigoid are still not entirely clear. In the etiology, both the genetic component and the acquired environmental component, such as, for example, exposure to UV rays or taking certain drugs, seem to contribute.
- Bullous pemphigoid may be associated with other diseases with immunological pathogenesis, such as lichen, thymoma, systemic lupus erythematosus (SLE), rheumatoid arthritis and myasthenia gravis.
Pemphigoid Bolloso: is it contagious?
Bullous pemphigoid is not contagious, therefore it is not transmitted either by accidental contact with the lesions, or through blood transfusions.
Symptoms and Complications
Bullous pemphigoid can occur in numerous clinical varieties, based on the site of the blisters, on their morphology and on the clinical course.
The main forms are the circumscribed one (localized bullous pemphigoid) and the generalized one.
Pemphigoid Bolloso: characteristics of skin lesions
- Bullous pemphigoid is characterized by the gradual appearance of blisters and strained bubbles of various sizes. These lesions arise on normal-looking skin or on the edge of erythematous plaques . The content of the bubble is clear or serum-blood .
- During the course of the disease, the rupture of the bubble's pemphigoid bubble roof results in superficial erosions with sharp edges that evolve into brown-blackish crusts . These lesions undergo progressive re-epithelialization, therefore they generally heal without the formation of scars or atrophy.
- Skin lesions of bullous pemphigoid are accompanied by itching, which may present varying degrees of intensity (in most cases, the itchy sensation is mild to moderate).
- In bullous pemphigoid, the appearance of tense bubbles can be preceded by a prodromal phase, characterized by the simultaneous presence of many different erythematous-edematous lesions (erythema, pomfi, papules, vesicles and inflammatory plaques), similar to eczematous or urticarial reactions.
Pemphigoid Bolloso: which venues are affected?
The areas most frequently affected by bullous pemphigoid are the trunk and the extremities (especially the flexor surfaces of the lower limbs).
In about one third of patients, there is the concomitant presence of lesions of the mucous membranes . In most cases, bullous pemphigoid presents with desquamative erosions and / or gingivitis in the oral cavity. Lesions can also occur at the level of the pharynx, ocular conjunctiva, nose and genitals.
Course of Pemphigoid Bolloso
Bullous pemphigoid has a chronic-relapsing course and a relatively benign prognosis .
Exacerbations of the disease are generally less severe than the initial episode and interspersed with long clinical remissions.
The course of bullous pemphigoid can be distinguished in two phases:
- Initial phase or urticarial : it is characterized by the appearance of intensely itchy erythematous patches; this aspect makes the pemphigoid bullous difficult to diagnose, since the pathology tends to present with lesions similar to hives, erythema or eczema.
- Overt or blunt phase : it can last many months and is characterized by the appearance of large, tense bubbles. Subsequently, these lesions evolve into erosions or crusts at sites where the bubbles break and undergo spontaneous healing, without hesitating in scarring.
The general condition is not compromised: although hospitalization is usually necessary to check for complications, the patient does not present other problems.
Pemphigoid Bolloso: possible complications
In elderly people, bullous pemphigoid can cause a series of complications related essentially to prolonged use of corticosteroids .
This class of drugs can, in fact, be responsible for a series of adverse effects ranging from diabetes to hypertension and osteoporosis. For this reason, it is important that patients with bullous pemphigoid in high-dose corticosteroid therapy are monitored closely.
Diagnosis
The clinical presentation of bullous pemphigoid is usually characteristic, but a confirmation skin biopsy is always performed. The histological examination following the bioptic sampling allows to ascertain or exclude the histological aspects of the disease, revealing the presence of sub-epidermal bubbles.
Furthermore, in the diagnostic procedure it is useful to search for tissue and circulating autoantibodies directed against specific antigens of the dermoepidermal junction ( direct and indirect immunofluorescence ): in all patients with bullous pemphigoid, IgG antibodies and C3 deposits are found (fraction of complement system that is activated in the presence of inflammation, chronic infections or autoimmune diseases) at the level of the basement membrane of the epidermis.
In some cases, eosinophilia can result from blood tests.
In the case of bullous pemphigoid, the Nikolsky sign is negative, therefore exerting a small lateral pressure on the healthy perilesional skin does not cause the epidermal detachment. This maneuver allows confirmation of the presence of acantholysis which is found, for example, in pemphigus vulgaris.
Differences with pemphigus
During the investigations aimed at establishing the diagnosis, it is important not to confuse the bullous pemphigoid with pemphigus vulgaris, another autoimmune skin disorder with similar clinical manifestations.
- Unlike pemphigus, which is also much rarer, bullous pemphigoid is typical of senile age and presents a substantially benign course, with periods of spontaneous remissions alternating with recurrences.
- Due to its characteristics, pemphigus tends to involve mainly the mucous membranes, as well as the skin; this occurs only in one third of cases of bullous pemphigoid.
- Furthermore, in pemphigus blistering lesions are thinner and therefore more prone to breakage. The rupture of the bubbles, besides exposing the patient to the risk of infections, also determines the loss of fluids. This makes pemphigus a much more serious pathological condition.
Treatment and Remedies
The treatment of choice of bullous pemphigoid is based on the commitment of corticosteroids, taking into consideration the clinical severity of the disease:
- In cases with diffuse involvement, systemic therapy (eg prednisone) is indicated;
- For localized forms, with few bubbles and / or slow evolution, topical therapy with dermatocorticosteroids may be indicated.
If bullous pemphigoid is not responsive to corticosteroids or if the lesions are particularly large, the doctor may consider the use of immunosuppressive drugs (such as methotrexate, mycophenolate, mofetil, aziatoprine and cyclophosphamide) to control the disease and prevent side effects associated with prolonged use of corticosteroids. However, immunosuppressive therapy may also determine a series of side effects ranging from hepatotoxicity to alopecia, from nausea to increased susceptibility to infections.
Recent scientific studies have shown a certain efficacy of alternative therapies to those conventionally indicated. In particular, bullous pemphigoid appears to benefit from the administration of:
- Rituximab : is a monoclonal antibody specific for the CD20 antigen of B lymphocytes, that is, the potential producers of autoantibodies, whose binding triggers a series of reactions involving the destruction of these cells. Rituximab was apparently effective in inducing remission in some patients with pemphigus vulgaris and cicatricial pemphigoid, refractory to conventional therapy.
- Intravenous immunoglobulins (IVIg) : this therapy was found to be able to induce a lasting reduction of autoantibody titres with parallel control of the disease activity.
It should be noted, however, that in order to confirm the effectiveness of these new therapies and evaluate their therapeutic effect over time, further clinical investigations are needed.
In some cases, your doctor may also recommend taking calcium or vitamin supplements.
Pemphigoid Bolloso: dietary measures
The intake of high doses of corticosteroid drugs, such as prednisone, especially at the beginning of therapy when a shock effect is needed, needs to be associated with a high protein diet low in fat, salt and carbohydrates . This keeps calcium levels constant and, at the same time, mitigates some of the side effects due to drugs.
Prognosis
Bullous pemphigoid healing times are generally long: only after several months of drug therapy, about half of patients experience complete remission; however, a maintenance regimen is often needed to keep the disease under control.
Without treatment, bullous pemphigoid tends to resolve after 3-6 years from the appearance of the first lesions. In some cases, the prognosis is not favorable: the disease can be fatal in about a third of elderly and particularly debilitated patients.
