What is pemphigus and what are its causes?

Pemphigus is a chronic, recurrent, severe intraepidermal acantholytic bullous skin disease. So what causes herpes? What are the clinical manifestations?

Causes

The cause of this disease has not yet been fully determined, but it is currently believed to be an autoimmune disease. The antigen of pemphigus is mainly desmosome, and the antibody is mainly IgG. Four IgG subtypes can be seen, and a few are IgA. The antibodies bind to epidermal cells, causing the spines to loosen. The cDNA sequence of pemphigus antigen has obvious homology with cadherin, so pemphigus antibodies also damage the adhesion function between epidermal cells, leading to loosening of spines.

Clinical manifestations

The age of onset varies greatly, with an average age of 50 to 60 years old, and the incidence rate is similar in men and women. In my country, pemphigus is traditionally divided into four types: vulgaris, proliferative type, deciduous type, and erythematous type.

1 Pemphigus vulgaris

It is the most common type of pemphigus. More than half of the patients first develop blisters and erosions in the oral mucosa, and then develop skin lesions that do not heal for a long time. Later, blisters ranging in size from soybeans to walnuts appear on normal-looking skin. The blister fluid is clear or slightly turbid, the blister walls are thin, loose and easily broken, and the Nikolsky sign is positive. The blisters rupture to reveal a red and erosive surface with a small amount of exudate or scab. The wound heals slowly and there is a burning pain. After healing, pigmentation and miliary papules remain. Blisters can occur anywhere on the body, most commonly on the head, face, neck, chest, back, armpits, and groin. There may be nail dystrophy, acute paronychia, and subungual bleeding. Severe pemphigus during pregnancy may lead to premature birth and stillbirth.

2. Pemphigus vegetative

The age of onset is younger. Skin lesions often occur in seborrheic areas, such as the head, face, armpits, navel, chest, back, pubic area, etc. Initially, it appears as flaccid blisters, which are very easy to rupture and form erosive surfaces and fungoid and papillary hyperplasia, which are particularly obvious at the friction sites. The surface of the lesion exudes serous or purulent fluid, is covered with a thick scab, and is surrounded by an inflammatory red halo. The lesions gather in groups or expand and merge into patches, with a fishy smell. Skin damage may occur before or after mucosal damage. The subjective symptoms are not obvious. During the course of the disease, due to secondary bacterial infection, symptoms such as high fever sometimes occur. The lesions are sometimes severe and sometimes mild, and the course of the disease is longer than that of the common type. There are two types of the disease: (1) Severe (Neumann type): The skin lesions are blisters and bullae, which rupture to form hypertrophic granular erosive surfaces that bleed easily. The proliferative plaques formed have serum and pus exudates and are surrounded by small pustules. The borders erode and new proliferative plaques form, and eventually these proliferative lesions become dry, hyperkeratotic, and fissured. This type of disease has a long course and is difficult to relieve on its own before the application of glucocorticoids. (2) Mild (Hallopeau type): Early skin lesions are characterized by pustules rather than blisters. After the blister ruptures, a proliferative plaque is formed. There are small pustules around the plaque. A variety of bacteria can be cultured within the lesions. The disease is chronic, the condition is mild, it can be relieved on its own, and the prognosis is good.

3. Pemphigus foliaceus

Most cases occur on the head, face, and trunk with normal-looking skin. The Nikolsky sign is positive, the blister walls are thin, easily ruptured, and dry quickly to form a thin yellow-brown scab that is attached in the center and free at the edges. The area under the scab is moist and gradually spreads to the entire body. The skin is dark red, covered with a large number of leaf-shaped scabs, and has a foul odor. Sometimes there are no obvious blisters and it resembles exfoliative dermatitis. Oral lesions are rare, and hair is sparse and often bald. Dystrophic changes may be seen in the nails. The patient feels itching or burning pain, and the systemic symptoms vary in severity, including fever, chills, mental disorders, etc. The course of the disease can last for more than 10 years, the prognosis is good, and it can be easily controlled by glucocorticoids, and some patients can achieve complete remission.

4. Pemphigus erythematosus

Also known as Senear-Usher syndrome. Skin lesions occur on the head, forehead, nose, cheeks, and ears, and sometimes the chest, back, armpits, and groin can also be affected, but rarely the limbs. The skin lesions on the head and face are similar to discoid or systemic lupus erythematosus and seborrheic dermatitis. There are lipid scales and yellow crusts on the localized erythema. One to several months after the above-mentioned skin lesions appear, flaccid bullae suddenly occur on the chest, back and limbs. The blister walls are thin and easy to break, the erosion surface gradually expands, and there is a lot of exudate. The surface often forms dirty, dark brown scabs and thick fat scabs that are not easy to fall off. The prognosis is brown pigmentation. Blisters appear one after another, and Nikolsky's sign is positive. There is generally no mucosal damage. The patient felt itchy but the systemic symptoms were not obvious.