Urticaria consists of migrating, clearly demarcated, erythematous, pruritic plaques on the skin.
Urticaria may also be associated with angioedema Angioedema is swelling of the deep layers of the skin and subcutaneous tie. It is usually an acute mast cell-mediated reaction after exposure toü. Learn more accompanying resulting from mast cell and basophil activation in deeper layers of the dermis and subcutaneous ties, manifesting as edema of the face and lips, extremities, or genitals. Angioedema may occur in the intestine. Occur as colicky abdominal pain. Angioedema can be life-threatening when airway obstruction occurs because of laryngeal edema or swelling of the tongue.
Pathophysiology
Urticaria results from the release of histamines, bradykinin, kallikrein, and other vasoactive substances from mast cells and basophils in the superficial dermis, leading to intradermal edema caused by vasodilation of capillaries and veins (and occasionally caused by leukocytic infiltration).
This process may or may not be immune mediated.
The immune mediated mast cell activation Includes
Autoimmune diseases in which antibodies to IgE receptors functionally cross-link them and cause mast cell degranulation
The non-immune mediated mast cell activation Includes
Direct, non-allergic activation of mast cells by certain drugs
Drug-induced inhibition of cyclooxygenases, which activates mast cells by mechanisms that are as yet almost unknown
Activation by physical or emotional stimuli; this mechanism is poorly understood but may involve the release of neuropeptides that interact with mast cells
Etiology
Urticaria is classified as acute ( 6 weeks) or chronic (> 6 weeks); acute cases (70%) are more common than chronic cases (30%).
Acute urticaria (Professional.See table Some causes of urticaria Some causes of urticaria Urticaria consists of migrating, clearly circumscribed, erythematous, pruritic plaques on the skin. Urticaria may also be associated with angioedema resulting from mast cell and basophil activation. Learn more ) is most often caused by
A possible trigger (z. B. Drug, food ingestion, insect bite or sting, infection) may occasionally be identified.
Chronic urticaria is most often caused by
Chronic urticaria often persists for months to years until it resolves without the trigger being found.
Urticarial lesions (hives) are wandering, raised, itchy, reddish plaques caused by circumscribed dermal edema.
Figure provided by Thomas Habif, M.D.
This photo shows a positive ice cube test in a patient with idiopathic cold-induced urticaria. This photo was taken 5 min after the ice cube was removed.
Urticaria pigmentosa may also present as reddish plaque-like lesions on the skin.
These yellowish to reddish-brown spots and papules produce a linear "hive", when stroked and is a sign of systemic mastocytosis, also known as urticaria pigmentosa.
This photo shows reddish-brown spots on the back of a school-aged child. The infant shown here has abundant papulonodular. Plaque lesions of urticaria pigmentosa.
This photo shows light urticaria in a woman who had been wearing a tank top. These hives appear within minutes of sun exposure.
Urticular papules and vesicles on the extremities of an infant with bullous pemphigoid.
Dermography or skin writing may occur when the skin is easily scratched and raised red lines form.
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Assessment
Because there are no definitive diagnostic tests for urticaria, evaluation is based largely on history and physical examination.
Medical history
The current medical history Should include a detailed description of each episode of urticaria, including the distribution, size, and appearance of the lesions, their frequency of occurrence, the duration of each episode, and any previous episodes. The activities and contacts with possible triggering factors during, immediately before and within the last 24 hours before the onset of urticaria are to be observed. Clinicians should be especially vigilant after recent exercise, exposure to potential allergens (Professional.see table Some causes of urticaria Some causes of urticaria Urticaria consists of wandering, clearly demarcated, erythematous, pruritic plaques on the skin. Urticaria may also be accompanied by angioedema resulting from mast cell and basophil activation. Learn more ), contact with insects or animals, new detergents, soaps, or foods consumed for the first time, and ask about recent infections or stressful life events. The patient should be informed about the duration between a suspected trigger. The occurrence of urticaria as well as about the suspected triggers themselves are asked. Important accompanying symptoms are pruritus, rhinorrhea, swelling of the face and tongue, and dyspnea.
The examination of the organ systems Should focus on symptoms of causative disorders, including fever, fatigue, abdominal pain, and diarrhea (infection); heat or cold intolerance; tremor; or weight change (autoimmune thyroiditis Hashimoto's thyroiditis Hashimoto's thyroiditis is a chronic, autoimmune inflammation of the thyroid gland with lymphocytic infiltration. One finds (editor's note: initial) a painless. Learn More ); joint pain (cryoglobulinemia [systemic lupus erythematosus] Systemic lupus erythematosus Systemic lupus erythematosus is a chronic, multisystemic inflammatory disease with autoimmune etiology that occurs preferentially in young women. Common manifestations. Learn More ); butterfly erythema (systemic lupus erythematosus); dry eyes and dry mouth (Sjogren's syndrome Sjogren's syndrome (SS) Sjogren's syndrome (SS) is a relatively common, chronic, autoimmune, systemic inflammatory disease of unknown etiology. It is characterized by sicca symptoms. Learn More ); skin ulcers and hyperpigmented lesions after urticaria recedes (urticarial vasculitis); small pigmented papules (mastocytosis Mastocytosis Mastocytosis is a mast cell infiltration of the skin or other ties and organs. Symptoms are mainly due to the release of mediators andä. Learn more ); lymphadenopathy (viral disease, cancer, serum sickness); acute or chronic diarrhea (viral or parasitic enterocolitis); fever, night sweats, or weight loss (cancer) focus.
The Medical history should include a detailed history of allergies, including known atopic conditions (e.g. B. allergies, asthma, eczema), as well as known possible causes (z. B. Autoimmune diseases, cancer) include. All medications taken should be reviewed, including over-the-counter and herbal medications and especially any agents associated with urticaria (Professional.see table Some Causes of Urticaria Some Causes of Urticaria Urticaria consists of wandering, clearly demarcated, erythematous, pruritic plaques on the skin. Urticaria may also be associated with angioedema resulting from mast cell and basophil activation. Learn More ). Family history should include all cases of rheumatoid. Autoimmune diseases as well as cancer. The social anamnesis should include all previous travels. Any risk factors for the transmission of infectious diseases (z. B. Cover for hepatitis, HIV).
Physical examination
When measuring vital signs, look for the presence of bradycardia or tachycardia and tachypnea. The general examination should immediately look for signs of respiratory distress as well as cachexia, jaundice, or agitation.
On examination of the head, swelling of the face, lips, or tongue, scleral icterus, butterfly erythema, a tender and enlarged thyroid gland, lymphadenopathy, or dry eyes and dry mouth should be noted. The mouth and throat should be examined, and the sinuses should be palpated and x-rayed for signs of occult infection (z. B. sinusitis, dental abscess).
Examination of the abdomen should note any swelling, hepatomegaly, splenomegaly, and tenderness. Neurologic examination should look for any tremors and hyper- and hyporeflexia. Examination of the musculoskeletal system should note inflamed or deformed joints.
Skin examination should note the presence and distribution of urticarial lesions, as well as any cutaneous ulceration, hyperpigmentation, small papules, or jaundice. Urticular lesions usually present as clearly demarcated, transient swellings involving the dermis. These swellings are usually red. Vary in size from a pinprick to large affected areas. Some lesions may be very large. In other cases, smaller urticarial lesions may confluent. However, skin lesions may not be present at the time of the medical examination. During the examination, z.