Erythema multiforme rash

Introduction Polymorphous erythema is an acute self-limiting inflammatory skin disease, often associated with mucosal damage, rash is pleomorphic, typical damage is target or iris-like damage. Can be caused by a variety of reasons, can be related to infected bacteria, viruses (especially herpes simplex virus), enzymes, protozoa, but also some drugs, such as sulfonamides, barbiturates, salicylates and biological products It is ill, and people are related to the cold.

Cause

The etiology of polymorphic erythema has not been fully understood so far, but is generally considered to be a skin disease caused by allergies. In recent years, the relationship between this disease and herpes simplex virus has attracted attention. It has been pointed out that more than 30% of patients with erythema multiforme are caused by herpes virus and have been confirmed by experiments, that is, after intradermal injection with herpes simplex virus antigen, it can cause the disease.

In addition, some cases are often caused by sulfa drugs, antipyretic and analgesics, sedative sleeping pills, antibiotics, etc.; some patients with chronic disease infections, such as tonsillitis, otitis media, sinusitis, Chronic attachment inflammation and other related; some are one of the clinical symptoms of the disease in the body, such as rheumatic fever, typhoid fever, wave heat, infectious mononucleosis, malignant granuloma and various malignant tumors can be accompanied by polymorphic erythema Some patients are caused by eating daily food such as fish, eggs, etc.; and the reason for a considerable number of diseases is still difficult to ascertain.

an examination

Polymorphic erythema often occurs in the spring and autumn, and often begins to get sick. Prodromal symptoms include hypothermia, headache, limb weakness, joint and muscle soreness. Some patients may be susceptible to herpes simplex or upper respiratory tract infection at the same time or before the onset of illness. The rash occurs in the face and neck and the distal extremities. The mucous membranes such as the mouth and eyes can also be affected. Skin lesions showed pleomorphism, including erythema, maculopapular rash, blisters, bullae, purple spots and wheal, but plaque and erythema were the most common. Typical damage color is internal UV red, and blisters can appear in the center. The appearance is very peculiar, and the rashes are clearly defined in the shape of the target. This is the so-called iris-like lesion. Seeing such a rash is helpful for diagnosis. Itching or mild pain and burning sensation in the affected area. In the onset of the disease, there is generally no obvious systemic symptoms, the course of the disease is self-limiting, and the skin lesions are expected to subside after about 2 to 4 weeks, but often relapse.

Differential diagnosis

According to the disease, the polymorphic rash and the predilection site are not difficult to diagnose. However, it should be differentiated from frostbite, drug eruption (polymorphic erythema), herpes-like dermatitis, and body lice.

(1) Frostbite occurs in winter. Occurs in the exposed parts of the hands, feet, auricles, nose and cheeks, the skin lesions are dark red or purple red edematous erythema, severe cases may appear blisters, erosion, but generally no iris-like damage, without mucosal damage.

(B) drug eruption erythema multiforme drug eruption performance can be similar to polymorphic erythema, but there is a clear history of medication, no seasonal and certain good hair.

(C) toxic epidermal necrolysis (Lyell disease) should be differentiated from severe erythema multiforme. The disease is acute, and after rapid, the rash is initially on the face, neck and chest, and quickly spread to the whole body. The skin lesions are twice burned and the necrosis is loosened. The skin is dark and red, and the Nissl sign is positive.

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