Etiology
Etiology: The etiology of the disease is complex and is generally thought to be related to infections, drugs, estrogen, and other diseases.
1. Streptococcal infection
In some patients, it can occur after upper respiratory tract infections, pharyngitis and acute tonsillitis.
2. Tuberculosis infection
There is increasing evidence that the disease is closely related to tuberculosis infection. Domestic statistics combined with tuberculosis infection, or old tuberculosis lesions, or positive nodulin test, accounting for more than 60%, the disease is considered to be an allergic phenomenon of the body to tuberculosis bacteria or their toxins.
3.Drugs
Certain drugs, especially bromides, sulfonamides and oral contraceptives, are the most common causes of the disease.
4, the disease is a skin metaplasia caused by many causes, the true pathogenesis is not clear. It is thought that the disease is a delayed metamorphosis of blood vessels to microorganisms or other antigens.
5.Other diseases
Other diseases such as autoimmune disease, ulcerative colitis and nodular disease can be accompanied by erythema nodosum. In addition, acute and chronic leukemia, can also be accompanied by the disease.
Erythema nodosum
It is commonly found on the extensor side of the calf, with the clinical manifestation of red or purplish-red painful inflammatory nodules, which is common in young women. The lesions occur suddenly as bilateral symmetrical subcutaneous nodules, ranging from fava bean to walnut, with a number of 10 or more, with self-conscious pain or pressure, and medium hardness. In the early stage, the skin color was light red, the surface was smooth and slightly elevated, and after a few days, the skin color turned dark red or greenish red and the surface became flat.
After 3 to 4 weeks, the nodules gradually fade, leaving temporary pigmentation, and the nodules always do not ulcerate. The lesions are usually found on the front of the shins, but also on the thighs, upper arms and neck, and rarely on the face.
Chronic erythema nodosum differs from acute erythema nodosum in that it often occurs in older women, the lesions are unilateral or, if bilateral, asymmetric, and are not associated with systemic symptoms other than joint pain. The nodules are not painful and softer than acute erythema nodosum.
Examination
1.Blood routine examination
The white blood cell count is usually normal or mildly elevated, but in the initial stage, when accompanied by high fever, tonsillitis or pharyngitis, the white blood cell count and neutrophil count may be significantly increased. 2/3 of patients have increased blood sedimentation. Rheumatoid factor may also be positive. Serum β2 microglobulin has been measured to be elevated.
2. Immunological examination
In the presence of tuberculosis, the tuberculin test may be positive.
3.X-ray examination
When the primary disease is tuberculosis, enlarged hilar lymph nodes are often found. It is reported in the literature that young women aged 16 to 30 years old with erythema nodosum and X-rays showing enlarged lymph nodes in both pulmonary hilum are called Buner syndrome, and it is believed that enlarged lymph nodes in the pulmonary hilum of such patients are actually a manifestation of systemic erythema nodosum.
4.Pathological examination
The main pathological changes occur in the subcutaneous fatty lobular septum. In the early acute inflammatory reaction stage, it is mainly neutrophil infiltration, accompanied by a small amount of lymphocytes, eosinophils and a small amount of red blood cell extravasation. As the disease progresses, the neutrophils quickly disappear and are replaced by lymphocyte, plasma cell and histiocyte infiltrates. In the fatty lobular septum, giant cells and granulomatous changes may appear. Vascular and fatty lobule injury is not evident.
Differential diagnosis
1.Hard erythema
The lesions are larger than those of erythema nodosum and have a long course. They may spontaneously break down and form ulcers, leaving different degrees of atrophy after healing.
2.Regressive febrile nodular non-suppurative lipofuscinosis
Regressive febrile nodular nonsuppurative lipofuscinosis is a nodular erythematous lesion, mainly located on the chest, abdomen, femur and buttocks, appearing in clusters and disappearing with local atrophy and disc-shaped depressions, with fever in each episode and pathological changes of subcutaneous fatty lobulitis.
3. Subacute nodular wandering lipofuscinosis
Subacute nodular wandering lipofuscinosis appears as a nodular erythema-like rash on the lower leg, usually early in the course of the disease can occur unilaterally, painless, eccentric enlargement, bright red edges, central whitening, can gradually flatten and form plaques, size 10 to 20 cm, duration ranging from two months to two years, performance with pigmentation, also known as wandering nodular erythema.
Treatment
1.Systemic treatment
(1) Find the cause of the disease and treat it accordingly. In the acute stage, bed rest, elevate the affected limbs, avoid cold and strong labor. For those with obvious infection foci, antibiotics can be used.
(2) For painful cases, take oral analgesics and non-steroidal anti-inflammatory drugs, such as indomethacin (anti-inflammatory pain) and ibuprofen. If there is obvious infection, give antibiotics. In severe cases, corticosteroids, such as prednisone (prednisone), or betamethasone/dipropionate (Depo-Provera) intramuscular injection, once every 3 weeks, can quickly control the disease. Alternatively, 10% potassium iodide combination can be given 3 times a day for 2 to 4 weeks.
This method is safe and effective, but it should be noted that long-term application can lead to hypothyroidism. If the disease is stubborn, hydroxychloroquine and aminophenyl sulfone can be applied, and Chinese herbal medicine, Leigongteng tablets or Kunming Shanhai Su tablets can also be taken. Systemic treatment can also be used ultraviolet light, wax therapy, transheat or audio electrotherapy.
2.Local treatment
The principle of local treatment is anti-inflammation and pain relief. External use of fish boron ointment, 10% camphor ointment dressing or 75% alcohol local wet compress, in addition to the external application of corticosteroid ointment, has a pain-relieving effect. Can also be injected into the lesion about 0.3 ml of de-inflammatory pine suspension plus 2% procaine solution injection, the nodules continue to severe pain has a significant effect.