Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ Urticaria ++ Figure 16-1 Urticaria A wheal is an edematous papule that may enlarge to form a pink, sharply circumscribed, elevated plaque. The typical lesions of urticaria, pictured in Figs. 16-1 and 16-2, have a suggestion of central clearing. Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ Figure 16-2 By definition, the individual lesions of urticaria evolve quickly and resolve within 24 to 48 hours. They are usually accompanied by severe pruritus. Urticaria is an extremely common disorder, and the etiology often remains unknown. In most children, the problem resolves spontaneously over time. Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ Figure 16-3 Urticaria Larger, more geographic lesions are pictured in Figs. 16-3 and 16-4. In the cases where a cause is established, the most common etiologies of urticaria are medications, foods (eg, nuts, strawberries, shellfish, and other seafoods), and viral and bacterial infections. Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ Figure 16-4 Autoimmune disease, such as autoimmune thyroiditis, and malignancy are extremely rare causes. In the child with chronic urticaria, it is often difficult or impossible to identify a single cause. In these patients, one attempts to control the development of new lesions with a daily schedule of nonsedating antihistamines. Graphic Jump LocationView Full Size||Download Slide (.ppt) +++ Physical Urticarias ++ Figure 16-5 Physical urticarias There are urticarias in which stroking, pressure, cold, heat, or sun exposure are causative. Figure 16-5 shows a wheal produced by stroking the skin with a degree of force that would ordinarily cause nothing more than transient erythema. The phenomenon, called dermographism, is present in a small percentage of normal individuals. Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ Figure 16-6 Figure 16-6 shows a large wheal produced by resting an ice cube on the forearm. Cold-induced urticaria may be acquired or inherited. In the most common, acquired form, patients develop lesions shortly after ingesting cold foods or liquids or shortly after exposure to a drop in environmental temperature. Patients with this form of sensitivity are at risk for laryngeal edema or circulatory collapse as a result of significant cold exposure. Antihistamines or doxepin are of some help in preventing attacks. In a very rare syndrome, contact of the skin with water, without respect to its temperature, produces wheals (aquagenic urticaria). Graphic Jump LocationView Full Size||Download Slide (.ppt) +++ Erythema Multiforme ++ Figure 16-7 Erythema multiforme This disorder is termed multiforme because the morphology of its lesions is so variable. The primary lesion is most often an erythematous macule that evolves into a papule. Early in the course, these lesions may easily be mistaken for urticaria. Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ Figure 16-8 As the lesions enlarge, they form ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.