You are at a wedding reception and one of the guests develops the rapid onset of pruritic, diffuse, raised, edematous papules and plaques surrounded by a zone of erythema without surface alteration. There is expansion and coalescence with areas of central clearing. After a few hours, the eruption spontaneously resolves. The patient reports that a similar eruption occurred a year ago that also spontaneously resolved within several hours. The image below represents the histopathological findings associated with this condition. The epidermis is unremarkable. Which of the following regarding this patient’s condition is INCORRECT?
A) Although this condition has characteristic clinical and histopathological findings, it is completely nonspecific in regards to etiology.
B) Some chronic forms of the condition are associated with IgG autoantibodies that cross-link the alpha subunit of the high-affinity IgE receptor on mast cells and basophils.
C) This patient most likely has the acute form of this condition since the two eruptions only lasted a few hours and occurred greater than 6 weeks apart.
D) Common inciting triggers for the acute form of this condition include hot and cold temperatures, exposure to water and UV light, stress, exercise, and vibration and direct pressure to the skin.
E) Severe swelling and edema of the lips, eyes, face, hands, and feet accompanied by airway obstruction is considered a medical emergency that may be treated with epinephrine.
The biopsy reveals a sparse perivascular lymphocytic infiltrate with scattered interstitial neutrophils and rare eosinophils. The epidermis is uninvolved (not visualized). The findings are consistent with urticaria. Urticarias are common, transient eruptions that affect roughly 15% of the population at some time in life. They comprise palpable erythematous papules or wheals that lack surface alteration and wax and wane without a clinical residuum. Lesions of urticaria are typically “here today and gone tomorrow,” unlike urticarial rashes induced by drugs or urticarial vasculitis, in which the individual lesions may resemble urticaria but persist for several days. Urticarias may be acute or chronic; the latter defined as transient and fluctuating eruptions that last longer than 6 weeks. In general, acute urticaria typically reflects a type I (IgE-mediated) hypersensitivity response, while chronic urticaria has a more complex pathogenesis including physical, IgE-mediated, immune-complex-, or histamine-releasing agent-mediated types (Table 2-1A). Both immunologic and non-immunologic mechanisms may cause mast cell or basophil degranulation. The main mediators include histamine, prostaglandins, and interleukin 1 (IL-1). While patch testing may occasionally reveal the inciting antigen in acute urticaria, the majority of acute and chronic cases remain idiopathic.
Acute urticaria. Wheals with white-to-light-pink color.