Summary about Disease
Urticaria, commonly known as hives, is a skin condition characterized by raised, itchy welts (wheals) that can appear anywhere on the body. Heat-induced urticaria, specifically, is triggered by exposure to heat, including hot weather, hot showers, or even exercise that raises body temperature. The welts can vary in size and shape and may appear and disappear quickly, sometimes within minutes or hours.
Symptoms
Raised, itchy welts (wheals) on the skin.
Welts that are red or skin-colored.
Welts that may blanch (turn white) when pressed.
Welts that vary in size and shape.
Welts that appear and disappear quickly.
Itching (pruritus), which can be severe.
Angioedema (swelling) may occur in severe cases, particularly around the eyes, lips, or tongue.
Causes
Heat urticaria is triggered by an increase in body temperature. Specific causes can include:
Exposure to hot weather.
Hot baths or showers.
Exercise or physical exertion.
Wearing occlusive clothing.
Sometimes stress can exacerbate the condition.
In some instances, the exact trigger isn't easily identifiable.
Medicine Used
Antihistamines: Primarily H1 antihistamines (e.g., cetirizine, loratadine, fexofenadine, diphenhydramine) to relieve itching and reduce the appearance of hives.
H2 Antihistamines: (e.g., ranitidine, cimetidine) May be used in conjunction with H1 antihistamines.
Corticosteroids: In severe cases, oral corticosteroids (e.g., prednisone) may be prescribed for short-term relief.
Epinephrine: For severe allergic reactions (anaphylaxis) involving breathing difficulties or swelling of the throat.
Topical Treatments: Calamine lotion or other anti-itch creams can provide some relief.
Omalizumab (Xolair): A monoclonal antibody used for chronic spontaneous urticaria, may be considered for severe, persistent cases unresponsive to other treatments.
Is Communicable
No, heat urticaria is not communicable. It is not contagious and cannot be spread from person to person.
Precautions
Avoid triggers: Identify and avoid activities or environments that cause heat-induced hives.
Stay cool: Keep your body temperature down by staying in air-conditioned environments, using fans, and taking cool showers or baths.
Wear loose-fitting clothing: Opt for breathable, lightweight fabrics that don't trap heat.
Hydrate: Drink plenty of water to stay hydrated, especially during hot weather or exercise.
Avoid strenuous activity: Limit intense physical exertion during hot conditions.
Identify and avoid other triggers: Some people may have other triggers that exacerbate urticaria.
How long does an outbreak last?
Individual welts typically disappear within a few minutes to a few hours. However, new welts may continue to appear, causing an outbreak to last from a few hours to several days, or even longer in chronic cases. The duration varies depending on the severity of the reaction and the individual.
How is it diagnosed?
Medical History and Physical Exam: A doctor will ask about your symptoms, triggers, and medical history. A physical exam will be conducted to observe the hives.
Trigger Identification: Identifying the trigger (heat) is crucial.
Allergy Testing: Allergy testing (skin prick tests or blood tests) may be performed to rule out other allergies that could be contributing to the hives, though heat urticaria itself isn't typically an allergic reaction in the traditional sense.
Challenge Testing: In some cases, controlled exposure to heat may be used to confirm the diagnosis, but this should only be done under medical supervision.
Timeline of Symptoms
The symptoms often appear quickly after exposure to heat:
Immediate: Within minutes of exposure to heat, itching may begin.
Minutes to Hours: Welts appear on the skin, varying in size and shape. The welts might be red, or skin-colored, and blanch when pressed.
Hours to Days: Individual welts fade within a few hours, but new ones may continue to appear, causing the outbreak to persist.
Chronic Cases: If the condition persists for more than six weeks, it is considered chronic.
Important Considerations
Angioedema: Be aware of signs of angioedema (swelling around the eyes, lips, or tongue), which can be a sign of a more severe reaction. Seek immediate medical attention if angioedema occurs with breathing difficulties.
Underlying Conditions: While heat urticaria is usually triggered by heat, underlying conditions may contribute to its development or severity.
Medication Interactions: Be aware of potential interactions between urticaria medications and other medications you are taking.
Stress: Stress can sometimes worsen urticaria symptoms.
Chronic Urticaria: If hives persist for more than six weeks, it is considered chronic urticaria, and further evaluation by a doctor or allergist may be needed.