GENERAL INFORMATION
Urticaria is an edematous and erythematous change of mucous membranes and superficial dermis with pale center and erythematous surrounding. With pressure, the lesions turn white. It is often itchy. It shows a symmetrical distribution. It can happen anywhere on the body.
Angioedema is edema of the lower layers of the dermis, subcutaneous tissue, and submucosa.
Urticaria Classification
Spontaneous urticaria
• Acute urticaria
• Chronic urticaria
physical urticaria
• Cold urticaria
• Late type pressure urticaria
• Hot urticaria
• Solar urticaria
• Dermographism
• Urticaria factitia
• Aquagenic urticaria
• Cholinergic urticaria
• Contact urticaria
Other
• Exercise-induced anaphylaxis/urticaria
• Popular urticaria (most often caused by insect bites)
• Lesions usually last less than 24 hours in acute urticaria-angioedema. But it just repeats. This condition, which is defined by patients as "hives that persists", can last up to 4-6 weeks. However, a single lesion never lasts longer than 24 hours.
• Chronic urticaria-angioedema is visually indistinguishable from acute disease. In this, a lesion lasts less than 24 hours. The only difference is the duration of the disease;
- Acute urticaria lasts less than 6 weeks.
- Chronic urticaria lasts longer than 6 weeks and has at least 2 attacks per week.
• The most common cause of acute urticaria in children is food and infections, and in adults drugs (penicillin and aspirin).
• The most common cause of chronic urticaria is idiopathic.
• Chronic idiopathic urticaria may be autoimmune. HLA DR4 is common in patients. There is no deposition of complement or immunoglobulin. In a group of patients with chronic idiopathic urticaria, the presence of autoantibodies that cause histamine release can be recognized by urticaria that occurs when 5 µL of the patient's own serum is injected intradermally (autologous serum inoculation test).
• Hyper or hypothyroidism can cause chronic urticaria (anti-TPO antibodies are high). Since autoimmune thyroid disease (Hashimoto's thyroiditis) can be seen in patients with chronic urticaria, autoantibodies should also be requested regardless of the results of thyroid function tests. Anti-IgEs formed in cases with chronic idiopathic urticaria activate the complement system and lead to the formation of anaphylatoxins. Since these anaphylatoxin receptors are only on the skin, the findings are localized to the skin in acute and chronic urticaria cases and there are no systemic findings.
• Parasitosis should be considered in chronic urticarias with eosinophilia. Insect bites should be considered more in papular urticaria.
• Urticarial vasculitis should be considered if urticarial plaques last >24 hours, do not fade with pressure, do not itch, and heal by bruising and pigmentation while healing.
Treatment
• Removal of antigen
• Antihistamines
• Glucocorticoids in severe cases
• 1/1000 IM adrenaline 0.01 mg/kg, maximum 0.5 mg in cases with diffuse urticaria
• Montelukast or Omalizumab can be used if the antihistaminic response is not good in chronic urticaria.
• Cyproheptadine is used in cold urticaria.
• Urticarial vasculitis: Methotrexate, colchicine, dapsone, hydrochloroquine
• Plasmapheresis can be performed for those who do not benefit from any treatment.
HERDITARY ANGIOEDEMA
• The cause is esterase inhibitor deficiency.
• This inhibitor prevents the classical way of activation of complement.
• It also stops fibrinolysis by inhibiting FXII.
• Type 1 (85%): Cl inhibitor cannot be made. OD passes.
• Type 2 (15%): Cl inhibitor is done, but it is dysfunctional.
Pathogenesis of hereditary angioedema
• Although activation of the complement system may contribute to the onset or severity of attacks in A in hereditary angioedema, the increase in vascular permeability that causes angioedema is associated with products of the contact system or kallikrein-kinin pathway. It significantly controls the contact system by inhibiting the Cl inhibitor plasma kallikrein and coagulation factor FXIIa. This inhibition suppresses the formation of bradykinin. Excessive bradykinin synthesis is the main cause of angioedema, as fibrinolysis cannot be inhibited in Cl inhibitor deficiency.
• The main mediator responsible for angioedema attacks is bradykinin.
• It binds to B2 receptors on vascular endothelial cells, leading to increased vascular permeability and therefore edema.
• It is characterized by recurrent episodes of edema that primarily involve the subcutaneous tissue, oropharynx, larynx, gastrointestinal tract, and genital area. Symptoms of the disease appear in the first 10 years.
• Symptoms such as recurrent facial and extremity swellings, acute, circumscribed edema (spontaneous in 72 hours), recurrent abdominal pain in the form of colic due to intestinal wall edema, vomiting, diarrhea, hoarseness, and stridor may be seen in the clinic. Itching and redness are usually absent.
• Amyloidosis, neural deafness, leg pain, erythema marginatum may be present.
Diagnosis
C4 and C2 decreased.
C4 drops both during and between attacks. Therefore, it is used as a screening test.
a-2 Globulin decreases.
Hereditary angioedema treatment
1- Long-term treatment:
• Long-acting Androgens (danazol) can be used because they increase Cl esterase inhibitor synthesis.
• Cl inhibitor concentrate (every 3-4 days)
• Epsilon aminocaproic acid reduces symptoms.
2-Acute attack treatment:
• Cl inhibitor concentrates - first choice treatment
• Fresh frozen plasma: Edema may increase in some patients (due to quinine substrates in FFP), so it should be used with caution in life-threatening cases.
• If no Cl inhibitor concentrate is available, racemic or IM epinephrine can be used in severe cases with airway obstruction.
Ecalantit: Kallikrein antagonist. It can be used in acute attack over 16 years of age.
Icatabant: Bradykinin type-2 receptor antagonist. It is suitable for use for all childhood.
No antihistamines or steroids are used
