What is it?
Bullous pemphigoid is a skin disease (dermatosis).
The latter is characterized by the development of large bubbles on erythematous plaques (red patches on the skin). The appearance of these bubbles causes lesions and is often the cause of itching.
It is an autoimmune disease, the result of a disruption of the immune system in the person affected. This regulation of the immune system consists in the production of specific antibodies against one’s own organism.
This pathology is rare but can be serious. It requires long-term treatment.
Although it is a rare disease, it is also the most common autoimmune bullous skin disease.
Its prevalence is 1 / 40,000 (number of cases per inhabitant) and mainly affects the elderly (on average around 70 years of age, with a slightly increased risk for women).
An infantile form also exists and touches the child during the first year of his life.
Symptoms of Bullous pemphigoid
Bullous pemphigoid is a dermatosis of autoimmune origin. The subject suffering from this disease therefore produces antibodies against his own body (auto-antibodies). The latter attack two types of protein: AgPB230 and AgPB180 located between the first two layers of the skin (between the dermis and the epidermis). By causing a detachment between these two parts of the skin, these autoantibodies cause the formation of characteristic bubbles of the disease.
The atypical symptoms of bullous pemphigoid are the appearance of large bubbles (between 3 and 4 mm) and light color. These bubbles occur mainly in areas where the skin is reddish (erythematous), but can also appear on healthy skin.
The epidermal lesions are located generally at the level of the trunk and limbs. The face is more often spared.
Cutaneous pruritus (itching), sometimes early with the appearance of bubbles, is also significant of this disease.
Several forms of the disease have been identified:
– the generalized form whose symptoms result in the appearance of large white bubbles and itching. This form is the most common.
– the vesicular form, which is defined by the appearance of tiny blisters in the hands with intense pruritus. This form is however less common.
– the urticarial form: as its name indicates, it is reflected by plaques of urticaria also causing important itching.
– the type of prurigo, whose itching is more diffuse but intense. This form of the disease can also cause, in the subject affected, insomnia. In addition, they are not bubbles that are identifiable in the form of prurigo but crusts.
Some patients may not have any symptoms. Others develop a slight redness, itching or irritation. Finally, the most common cases develop redness and itching.
Blisters may burst and form ulcers or open wounds.
The origins of the disease
Bullous pemphigoid is an autoimmune dermatosis.
This origin of the disease results in the production of antibodies (proteins of the immune system) by the body against its own cells. This production of autoantibodies leads to the destruction of tissues and / or organs as well as inflammatory reactions.
The true explanation of this phenomenon is not yet known. Nevertheless, certain factors have a direct or indirect link with the development of autoantibodies. These are environmental, hormonal, medicinal or genetic factors.
These autoantibodies produced by the affected subject are directed against two proteins: BPAG1 (or AgPB230) and BPAG2 (or AgPB180). These proteins have a structural role in the junction between the dermis (lower layer) and the epidermis (upper layer). Since these macromolecules are attacked by autoantibodies, the skin is peeled off and bubbles appear.
Moreover, no contagion is associated with this pathology.
In addition, the symptoms usually appear spontaneously and unexpectedly.
Bullous Pemphigoid is however not:
– an infection;
– an allergy;
– a condition related to lifestyle or diet.
Risk factors for Bullous pemphigoid
Bullous pemphigoid is an autoimmune disease, in that it is not a hereditary disease.
Nevertheless, the presence of certain genes would be a risk of development of the disease in people carrying these genes. Either there would be some genetic predisposition.
This risk of predisposition is, however, very low.
Since the average age of disease development is around 70 years, the age of the person may be an additional risk factor for the development of bullous pemphigoid.
Moreover, it should not be overlooked that this pathology is also defined through an infantile form.
In addition, a slight predominance of the disease is visible in women. The female sex is therefore an associated risk factor.
Prevention and treatment of Bullous pemphigoid
The differential diagnosis of the disease is mainly visual: appearance of clear bubbles in the skin.
This diagnosis can be confirmed by a skin biopsy (taking a sample from the damaged skin for its analysis).
The use of immunofluorescence can be used in the detection of antibodies following a blood test.
The treatments prescribed in the context of the presence of bullous pemphigoid aim to limit the development of bubbles and heal the bubbles already present in the skin.
The treatment most commonly associated with the disease is general corticosteroid therapy.
However, for localized forms of Pemphigoid Bullosa, topical corticosteroid therapy (acting only at the place where the drug is applied), associated with Class I dermatocorticoids (a drug used in the local skin treatment).
A prescription for antibiotics of the tetracycline family (sometimes associated with vitamin B intake) may also be effective by the doctor.
Treatment is often prescribed in the long term and is effective. Moreover, a relapse of the disease is sometimes observable after stopping treatment.
After diagnosis of the presence of bullous pemphigoid, the consultation of a dermatologist is strongly recommended.