Urticaria (forms)

Spontaneous urticaria

The spontaneous form of the disease is characterized by the fact that characteristic skin lesions occur without any obvious external exposure (trigger). The physician cannot clearly link the appearance of wheals to physical exertion, contact with water, exposure to low temperatures, or other external irritants.

The key criterion for classifying spontaneous urticaria is the total duration of the disease course. Based on the temporal factor, two main subgroups are distinguished:

• Acute spontaneous urticaria. The diagnosis is established if the total duration of clinical symptoms (appearance of wheals) does not exceed 6 weeks.
• Chronic spontaneous urticaria. This form is diagnosed when the disease becomes protracted, and wheals appear periodically or continuously for more than 6 weeks.

Physical (inducible) urticaria

Physical urticaria represents a heterogeneous group of conditions. The main difference from the spontaneous form is that wheals appear strictly in response to a specific physical stimulus rather than an infectious agent, food allergen, or drug.

Depending on the nature of the physical impact, several specific variants are distinguished:

1. Dermographic urticaria. It is the most frequent form in this group. The trigger is mechanical contact, primarily friction. It is characterized by the very rapid appearance of skin lesions—typically 1–5 minutes after exposure.
2. Pressure urticaria. Triggered by pressure applied to the skin. An important diagnostic feature is the delayed onset of wheals: symptoms develop significantly later, usually 3–12 hours after the stimulus.
3. Cold urticaria. Occurs upon contact of the skin with cold (cold air, objects). In clinical practice, this form is classified as potentially dangerous.
4. Cholinergic (heat) urticaria. Develops as a result of contact with hot objects. Unlike cold urticaria, it is significantly less common.
5. Solar urticaria. The provoking factor is ultraviolet radiation, including direct sunlight and tanning beds.
6. Vibratory urticaria. A specific form in which any vibratory impact on the tissues acts as the trigger.

Chronic pathology in pediatrics: Bronchial asthma

When considering allergic and immunological conditions in children, the general disease background must be taken into account. In pediatric practice, the leading chronic pathology showing a pronounced upward trend is bronchial asthma (BA).

• Epidemiology: The prevalence of bronchial asthma in the Russian Federation ranges from 1–5%, heavily depending on the specific observation region.
• Age of manifestation: The disease has a clear age specificity. The vast majority of clinical cases—about 80%—debut in early childhood, specifically before the child reaches 5 years of age.
• Social burden: Bronchial asthma is a life-threatening condition. It imposes a massive burden on the healthcare system, being a frequent cause of emergency hospitalizations. Furthermore, the pathology critically reduces patients' quality of life, which in practice is often manifested by regular school absenteeism.

Class and exam questions

What else to study on this topic

• Criteria for the potential danger of cold urticaria and the risk of anaphylaxis.
• Mechanisms of wheal formation under physical impact.
• Causes of the delayed reaction in pressure urticaria (3–12 hours).
• The link between ultraviolet radiation (sun, tanning beds) and the appearance of wheals.
• The role of bronchial asthma in reducing quality of life and in the structure of emergency hospitalizations.

Other topics in "Chapter 5. Allergic Diseases"

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