Acute and Chronic Urticaria?

“No matter how many hives may arise, they always are transient. But also, the process itself is extremely acute as one usually does not have it longer than one to several days. Acute urticaria is evanescent. However, under certain circumstances, the eruption of hives may consist of exacerbations and remissions that last for weeks, months or years, i.e., urticaria recidiva or chronic urticaria.”
Kaposi M. Urticaria. In: Pathologie und Therapie der Hautkrankheiten. (Pathology and Therapy of Skin Diseases) Vienna, Austria: Urban and Schwarzenberg, 1893:324–5.

“Most cases [of urticaria] are transient (acute) and the etiology is usually detected. On the other hand, chronic urticaria, which is arbitrarily defined as urticaria persisting for longer than six weeks, is idiopathic in approximately 75% of cases.”
Weedon D. Vasculopathic reaction pattern. In: Weedon D, ed. Pathology of the Skin. Edinburgh, Scotland: Churchill-Livingstone, 1992:215.

The terms “acute urticaria” and “chronic urticaria” are misleading because they imply that the hives themselves are acute or chronic, whereas in actuality hives in so-called acute and chronic urticaria not only last about the same amount of time, i.e., hours, but they are indistinguishable morphologically from one another. What then are acute urticaria and chronic urticaria, and do these designations have autnehticity?

By convention, if lesions of urticaria come and go for longer than a span of 6 weeks, the urticaria is considered to be chronic; if, however, those lesions wax and wane for a period of less than 6 weeks, the urticaria is judged to be acute. Whence did the number 6 derive? There is no basis for it whatever. It is arbitrary and makes no sense. Most persons who develop urticaria, whether consequent to such allergens as inhalants, ingestants, injectants, or infestations; from injection into the skin of nonallergenic substances, for example, histamine and 48/80; or from physical factors, such as cold, heat, UV light, or pressure, suffer from hives for a few hours only, at most for only a few days. If one were to divide urticaria, arbitrarily equally but more reasonably, into acute and chronic types, the division would be nearer to 48 hours than to 6 weeks.

A specific cause of urticaria practically never is found when hives have come and gone for a period of weeks, months, or years. In fact, no cause usually is discovered by physicians for hives that disappear completely in hours, never to return. The best chance for identifying the cause of urticaria lies with patients; sometimes they know the answer.

Hives are more or less the same morphologically, i.e., clinically and histopathologically, irrespective of their cause. Clinically, they are wheals, i.e., edematous papules with a pseudopod-like periphery, and, histopathologically, they are characterized by superficial, or superficial and deep, perivascular and interstitial mixed-cell infiltrates. Lymphocytes, neutrophils, and eosinophils are positioned around venules, and neutrophils and eosinophils are scattered among collagen bundles in the reticular dermis. The epidermis is unaffected in a lesion of urtica, and no edema, as evidenced by pallor, is detectable in the papillary dermis of it. The reason is that edema in urtica resides mostly in the reticular dermis, and it cannot be recognized because bundles of collagen present normally there are already separated from one another, in part by fluid of a fixative such as formalin. The findings just described are specific to urtica of all types and of all causes.

A reader should not be perplexed by the words “urticaria” and “urtica.” The former consists of individual lesions of the latter, i.e., the condition itself is urticaria and each of the lesions that constitute it is urtica.

In sum, hives, whether allergic or nonallergic in cause, have similar attributes clinical and histopathologic. Diagnosis of a specific type of urticaria cannot be made on histopathologic grounds alone. Sometimes the cause of urticaria may be inferred by clues clinical, e.g., pressure urticaria on soles, solar urticaria on sites of UV exposure, and cold urticaria limited to lips or oral mucous membranes when a popsicle is the offender. The illogical division of urticaria into acute and chronic types based on temporal considerations does not enhance understanding of the condition in general or of specific types in particular. There is no need for such division, and the sooner it is abandoned the better. The diagnosis should be urticaria, and a reasonable attempt should be undertaken to find the cause of it. If in that endeavor history fails, it is highly unlikely that prick tests for inhalant allergens, patch tests for contact allergens, serologic studies of blood, search for a focus of infection, elimination of particular foods and food additives from the diet, or provocation by particular foods and additives will succeed.

“For convenience, urticaria may be classified as either acute or chronic depending on the duration of the entire process. Acute urticaria evolves over a period of days or weeks (less than 6 weeks). Following this relatively short duration, there is complete involution with no further occurrences…Chronic urticaria is defined as episodic or continuous recurring wheals occurring for at least 6 weeks and generally much longer.”
Katz HI. Anaphylactic syndrome. In: Moschella SL. Hurley HJ, eds. Dermatology, 3rd ed. Philadelphia, PA: WB Saunders Co., 1992:288.

“The individual lesions arise suddenly, rarely persist longer than 24 to 48 hours, and may continue to recur for indefinite periods. Episodes of lesions less than 6 to 8 weeks’ duration are considered acute, whereas those persisting longer are termed chronic.”
Soter NA. Urticaria and angioedema. In: Fitzpatrick TB, Eisen AZ, Wolff K, et al., eds. Dermatology in General Medicine, 4th ed. New York, NY: McGraw-Hill International Book Co., 1993:1484.

“Urticaria/angioedema is considered to be acute if it lasts less than 6 weeks. Most acute episodes are due to adverse reactions to foods in children or to viral illnesses. Episodes of urticaria/angioedema persisting beyond 6 weeks are considered chronic and most likely represent idiophathic urticaria or urticaria that is autoimmune.”
Soter NA, Kaplan AP. Urticaria and angioedema. In: Freedberg IM, Eisen AZ, Wolff K, et al., eds. Fitzpatrick’s Dermatology in General Medicine, 6th ed. New York: McGraw-Hill, 2003:1129-30.

“All urticarias are acute initially. Some will become chronic after a period of time that is usually defined as 6 weeks or more.”
Grattan CEH, Black AK. Urticaria and angioedema. In: Bolognia JL, Jorizzo JL, Rapini RP, eds. Dermatology. London: Mosby, 2003:291.

“Acute episodes of urticaria generally last only several hours. When episodes of urticaria last up to 24 hours and recur over a period of at least 6 to 8 weeks, the condition is considered chronic urticaria.”
Mobini N, Toussaint S, Kamino H. Noninfectious erythematous, papular, and squamous diseases. In: Elder DE, Elenitsas R, Johnson BL, et al., eds. Lever’s Histopathology of the Skin, 9th ed. Philadelphia: Lippincott Williams & Wilkins, 2005:179.

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