Primary cryoglobulinemia is more common in young people and middle-aged people, and is slightly more common in women than in men. When the patient’s body surface temperature drops in cold, cold globulin in the blood vessels of the extremities becomes precipitated or jelly-like, blocking the capillaries and causing ischemic necrosis and vasospasm of the blood vessel walls, resulting in purpura and cold urticaria of the skin as the most common. What can cause cryoglobulinemia?
Cryoglobulin is a protein that precipitates when cold and dissolves when the temperature rises, and it can be divided into 3 types. Type I is monoclonal lineage type, that is, immunoglobulin of monoclonal origin, with four types of IgG, IgM, IgA and condensin; Type II is mixed type, consisting of two or more immunoglobulins, one of which is of monoclonal origin; Type III is polyclonal prototype. Type I is not complement resistant and usually causes large vessel injury by an unknown mechanism. Types II and III are both mixed types. Anti-complement, by activating the complement system for immune response and tissue damage, mainly causes small vessel damage. Abnormally increased cryoglobulins can be divided into primary and idiopathic according to their origin. The former is asymptomatic and is only detected during routine examinations, while the latter is often associated with immunoproliferative disorders, infectious disorders, etc.
The most common skin lesion is hemorrhagic purpura, which starts in the lower extremities and gradually extends to the femur, perineum and buttocks, and rarely extends to the upper extremities and oral mucosa. The rash is characterized by papules, petechiae, petechiae, small nodules, and in severe cases, blisters, macules, ulcers, and gangrene. Itching or burning may be conscious, and in severe cases, pain may be present. Next, cold urticaria, Raynaud’s phenomenon, reticular cyanosis, vasospasm of the extremities, and cyanosis are seen. Hyperpigmentation is seen in chronic cases. Arthralgia is a prominent symptom in patients with mixed cold globulinemia and is commonly seen in the hand and knee joints. Renal damage may manifest as acute or chronic nephritis, and may even lead to renal insufficiency or renal failure and death. The main manifestations of the nervous system are peripheral neuropathy manifested as abnormal sensation, numbness, motor impairment, and loss of tendon reflexes. Central nervous system involvement is rare. Other symptoms include hepatosplenomegaly, abdominal pain, pericarditis, and generalized lymph node enlargement.
The diagnosis of the disease is based on clinical manifestations and a significant increase in serum cryoglobulin. It should be noted that cryoglobulins are not easily detected after treatment with corticosteroids or after the improvement of the existing concomitant diseases. A temporary increase in cryoglobulins should also be excluded.