Overview.
Allergic cutaneous nodular vasculitis is a skin disease characterized by the formation of nodular lesions based on the pathology of fine vasculitis in the subcutaneous tissue of the lower extremities. The disease occurs more often in young and middle-aged women. The ratio of men to women is about 1:5, and the average age of onset is 30 years old. The onset of the disease has obvious seasonality, the vast majority of the late spring and early summer onset, the summer is more serious, after the fall to reduce, winter subside or residual, no obvious symptoms of nodular damage, the following year and recurrence.
Etiology
The etiology of this disease is unknown. Some patients have a clear history of tuberculosis or static tuberculosis foci, tuberculin skin test can be strongly positive, anti-tuberculosis drug therapy has a good effect; a small number of patients before and after the onset of a few days of fever, sore throat or tonsillitis, as well as anti-“O” elevation. At present, it is believed that this disease is related to the delayed-type allergic reaction induced by the infection of pathogenic bacteria or its metabolites, and it is a clinically independent disease, but the cause of the pathogenesis of the majority of cases is still unknown, and it may be related to allergy to a variety of factors.
Symptoms
All allergic cutaneous nodular vasculitis damage is first seen in both calves, especially in the lower two thirds of the calves, and is scattered, not limited to the extensor or flexor side. In the course of repeated attacks, it gradually involves the thighs and buttocks, and occasionally the forearms, with the thighs mostly in the lower part and the upper limbs mostly in the forearms. Patients often feel localized pain and tenderness before palpating the subcutaneous nodules. The number of nodules is often less than 10, usually about the size of a fava bean to a prune, with palpable edges and medium hardness. The initial damage is small and deep, mostly skin color or light red to bright red, with the extension of time, the color can be deepened. 3 ~ 4 weeks later, the red color subsides leaving mild hyperpigmentation spots, nodule damage completely subside later. There is also a more characteristic damage, its duration is longer, slightly larger than the previous damage, purple or dark red, the central skin is smooth and shiny, or the central skin has a sense of tenderness, or even flaking, but never broken, and there is no skin atrophy and depression phenomenon after absorption. The buttocks and thighs are deeper and generally harder, with non-red or light red skin that is only palpable. Posterior ankle lesions were flattened, round, reddish hard nodules with marked edema of the surrounding soft tissues. All damages are scattered, with a rare tendency to enlarge and fuse. Therefore, the damage pattern of the disease is not the same depending on the site of onset, location, depth and color.
Systemic symptoms vary according to the urgency of the onset of the disease and are generally characterized by drowsiness, malaise or loss of appetite. Fever is very variable, being absent in most cases, low in the afternoon in a few cases, rising after exertion, or high in the days before and after the onset of the nodules. In the more unusual cases, chills or even chills in the afternoon, followed by high fever, with sweating and fever subsiding at midnight, and as usual the next morning. There are no cases of persistent hyperthermia. When the number of damages is small, there is no obvious discomfort, but when there are more, the lower limbs feel weak and achy, muscle swelling and pain, or lower calf edema. In some cases, there may be wandering pain in the large joints of the limbs, mostly in the knee joints, but there is no redness, swelling and dysfunction.
Examination
1. Laboratory examination
There is no abnormality in blood, urine routine and liver and kidney function tests, some cases have elevated anti-“O”, rapid blood sedimentation and mucin level, IgG and IgA values are generally normal, complement C3 is low, circulating immune complex (CIC value) is slightly higher than normal, the value of lymphocyte transformation test (3H isotope measurement) is generally low, IL-2 value is low, NK cell value is normal, and NK cell value is normal. Lymphocyte transformation test (3H isotope assay) is generally low, IL-2 value is low, NK cell value is normal, and OT test (1:10,000) can be positive in most cases.
2. X-ray examination
Chest X-ray: some cases have old tuberculosis, occasionally active tuberculosis.
3. Histopathology
The lesions are confined to the subpapillary dermis and subcutaneous adipose tissue. The main lesions are vasculitis, subcutaneous fat tissue necrosis, granuloma and granuloma-like structures. All capillaries and small vessels were involved. Endothelial cell hypertrophy and hyperplasia were the most prominent of the canal wall lesions.PAS staining was negative and antacid staining was negative.
Diagnosis
1. The disease mostly occurs in young and middle-aged women.
2. The damage is below the buttocks and mainly involves the lower legs.
3. The basic damage is subcutaneous nodules, never broken, symmetrically distributed, not limited to the extension or flexion of the calf.
4. Recurrent and seasonal.
5. Systemic symptoms are rare, without signs and symptoms of other systemic involvement.
6. No other definite cause or trigger other than tuberculosis foci.
7. no complications such as reticular cyanosis and varicose veins.
Differential diagnosis
1. Erythema nodosum
Erythema nodosum is an acute inflammatory disease mainly involving subcutaneous adipose tissue, mostly seen in young and middle-aged women, preferably on the extensor side of the calf. Clinical manifestation is red or purple painful inflammatory nodules, ranging from beans to walnuts, common in young women, with limited course and easy to recur.
2. Hard erythema
It is common in young women, and often complicates with tuberculosis in other parts of the body. Tuberculin test is positive, but mycobacterium tuberculosis is seldom isolated from the lesions. It mostly occurs in the flexion side of calf, often single or several, the lesion is bigger than erythema nodosum, with a long course of disease, and it can break spontaneously and form ulcers, and there are different degrees of atrophy after healing.
Treatment
Since the lesions are mainly located in the lower limbs, for those who are in serious condition, in addition to drug treatment, activities should be minimized to shorten the course of the disease and reduce pain.
1. For cases with tuberculosis infection, anti-tuberculosis drugs should be used, such as oral isoniazid and ethambutol or rifampicin combination therapy, for six months to one year.
2. For cases without clear tuberculosis infection factors, traditional Chinese medicines such as Gui Zhi Fu Ling Pill plus heat-clearing and detoxifying medicines can be used to resolve blood stasis. Though Lei Gong Teng tablets or decoctions have some effect, they cannot be used for a long time because of their side effects.
3. Glucocorticoid therapy is effective, and in some cases the tuberculosis foci are cured after treatment.