Urticaria : local wheals and erythema in the dermis
Angioedema : a similar eruptions, but with larger edematous areas that involve subcutaneous structures as well as the dermis.
Cell mast degranulation : immune mechanism / non immune
Urticaria & angioedema are essentially anaphylaxis limited to the skins and subcutaneous tissues and can be due to :
Insect stings or bites
Ingestions of certain foods (eggs, shellfish, nuts or fruits)
Urticaria may accompany or even be the first symptom of several viral infections (including: hepatitis, mononucleosis, & rubella)
If acute angioedema is recurrent, progressive, and never associated with urticaria ® a hereditary deficiency should be suspected.
Symptoms And Signs
Pruritus (generally the first symptom) is followed shortly by the appearance of wheals that may remain small (1 to 5 mm) or may enlarge. The larger ones tend to clear in the center and may be noticed first as large (>20 cm across)
Rings of erythema
More diffuse swelling of loose subcutaneous tissue : dorsum of hands or feet, eyelids, lips, genitalia, mucous membranes.
Edema of the upper airways ® may produce respiratory distress, and the stridor may be mistaken for asthma
Multiple insecte bite
Rare, non urticaria, subcutan / submucous periodic edema, sick, some time larynx edema.
Edema ussually extremity and gastrointestine mucous
Recovery after 1-4 days.
Diagnosis : complement titers C4 dan C2↓
Urticaria is a self-limited condition that generally subsides in 1 to 6 days; hence, treatment is chiefly palliative. If the cause is not obvious, all nonessential medication should be stopped until the reaction has subsided.
Symptoms usually be relieved with an oral antihistamine (e.g. Dipenhydramine 5 mg / kg / 24 hr every 6-8 hr or cyproheptadine 0,25 mg / kg / 24 hr every 6 hr).
Corticosteroids (e.g. Prednisone 1-2 mg / kg / 24 hr PO) may be necessary for the more severe reactions, particularly when associated with angioedema.
Epinephrine 1:1000, 0.3 ml SC, ® should be the first treatment for acute pharyngeal or laryngeal angioedema.
This usually prevents airway obstruction, but one must be prepared to perform a tracheotomy and give o2
Prognosis : good