Pharmacist explains: A complete guide to the treatment and management of chronic urticaria

Author: Jie Hengbo Peking Union Medical College Hospital

Reviewer: Zhang Cuilian, Chief Pharmacist, Peking Union Medical College Hospital

Urticaria is a common immune-related skin disease, mainly manifested by wheals, itching and angioedema. According to statistics, the prevalence of urticaria in my country is about 0.75%. When the onset of wheals or angioedema lasts for more than 6 weeks, it is considered chronic urticaria. In this article, let the pharmacist solve your doubts about chronic urticaria!

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1. What are the symptoms of urticaria?

The main manifestations of urticaria are wheals and/or angioedema of varying sizes and shapes, most of which are accompanied by itching. Patients with severe conditions may also have symptoms such as fever, nausea, and vomiting.

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2. Why do you get urticaria?

The etiology of urticaria is relatively complex, including exogenous and endogenous factors.

1. Exogenous factors

(1) Physical factors: such as clothing rubbing against the skin, prolonged pressure on a certain part of the body, and exposure to sunlight.

(2) Food factors: such as animal protein (milk, eggs, seafood, etc.), fruits (strawberries, citrus, etc.), nuts (peanuts, walnuts, etc.).

(3) Environmental factors: such as the abundance of pollen in spring, or allergens such as dust mites that are common in the home environment.

(4) Drug factors: certain vaccines, some antibiotics (such as penicillin, sulfonamides), and serum preparations (such as immunoglobulin).

2. Endogenous factors

(1) Infection: such as influenza virus, Epstein-Barr virus, streptococcal infection, ascaris infection, etc.

(2) Mental factors: mental tension, stress, and mood swings.

(3) Autoimmune reaction: Autoimmune diseases, such as systemic lupus erythematosus, thyroid disease, etc.

Although the recurrence rate of urticaria is high, it is self-limiting to a certain extent, and most patients have a good prognosis.

3. Which departments should patients with urticaria go to for treatment?

It is usually divided according to the departments of different hospitals, and you can go to the allergy department, dermatology department, immunology department, etc. for treatment.

4. What is the drug of choice for treating chronic urticaria?

The first choice for the treatment of chronic urticaria is the use of second-generation antihistamines, such as cetirizine and loratadine. The conventional standard dose is used as the initial dose. If the condition is not well controlled within 1 to 2 weeks, the type of antihistamine can be changed, or the dose can be increased or multiple antihistamines can be used in combination; if the condition is effectively controlled, the dose can be gradually reduced and maintained at a lower dose. The course of treatment for chronic urticaria with antihistamines is usually not less than 1 month, and can be extended to 3 to 6 months if necessary. Therefore, the medication should be taken regularly, quantitatively, and cyclically as prescribed by the doctor.

5. What precautions should be taken when using medication for special groups?

1. Pregnant and lactating women There is limited information on the safety of antihistamines in pregnant and lactating women, especially in the early stages of pregnancy, and their use should be avoided as much as possible. In addition, since antihistamines can be secreted through breast milk, lactating women should avoid using such drugs as much as possible to avoid sedation in the infant. If this type of drug must be used, it is recommended that second-generation and third-generation antihistamines with lower central effects (such as levocetirizine, desloratadine, etc.) be used under the guidance of a doctor to reduce the risk of adverse reactions.

2. Children: Currently, there are many antihistamine dosage forms suitable for children on the market in China, such as loratadine syrup, cetirizine hydrochloride syrup, desloratadine dry suspension, etc. The instructions indicate that they can be used for infants and children over 6 months old. The specific choice should be made under the guidance of a doctor.

Since antihistamines have adverse reactions such as central nervous system sedation, in order to improve the safety of medication, first-generation antihistamines (such as diphenhydramine) are now rarely used in the treatment of chronic urticaria, except for acute attacks. Here, the usage and dosage, precautions, safety during pregnancy and medication information for children of the commonly used second-generation and third-generation antihistamines in clinical practice are listed for your reference.

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6. What other precautions should be taken?

1. Take the medicine regularly and on time, and do not take it only during the symptom onset period. Control the wheal and itching as the standard, and consider reducing the dosage after the symptoms are stably controlled for 1 to 2 weeks during medication.

2. Do not drive after taking the medicine. Antihistamines may cause drowsiness, dizziness and other reactions. The specific reactions and feelings vary from person to person. Please do not drive or engage in precision sports after taking the medicine.

3. Antihistamines will reduce the sensitivity of skin allergy test results and should be stopped for at least 3 days before testing for allergens.

7. In addition to antihistamines, what other drugs can treat urticaria?

1. If chronic urticaria is acutely aggravated, glucocorticoids (such as hydrocortisone) can be used for a short period of time, but the dosage must be gradually reduced after the condition improves. Long-term inappropriate use of topical hormone drugs may cause adverse reactions such as skin atrophy and capillary dilation.

2. If the efficacy is still poor after the application of the above two types of drugs, biological agents such as omalizumab can also be used as third-line treatment, and the dosage and frequency of medication need to be determined based on the total serum immunoglobulin E and body weight before treatment. It is particularly important to remind that subcutaneous injection may bring risks such as injection site reactions. You should choose carefully according to the doctor's advice.

3. In addition to the above treatment options, immunosuppressants (such as cyclosporine, tripterygium wilfordii polyglycosides, etc.), topical skin preparations (such as calamine lotion) and other drugs can also be used. The specific dosage regimen needs to be consulted by a specialist.

8. How to reduce the adverse reactions caused by drugs?

1. Adjusting the medication time to before going to bed every night can reduce the impact of adverse reactions of second-generation or third-generation antihistamines with lower central nervous system sedative effects on life and work.

2. If you use glucocorticoids, you should stop taking them as directed by your doctor after your symptoms are relieved. Usually, the course of treatment should not exceed 2 weeks. If your symptoms are not relieved after 1 week of medication, you should communicate with your doctor in a timely manner.

3. It is recommended that people who use immunosuppressants or take antihistamines for a long time should regularly test biochemical indicators such as liver and kidney function. If abnormalities are found, they should seek medical attention in time. Because such drugs may cause reproductive toxicity, people who are planning to have children should use immunosuppressants with caution.

9. What precautions should patients with urticaria take in their daily lives?

For urticaria patients with clear causes, or whose allergens have been identified through skin irritation or serum tests, they should stay away from allergens or stimulating conditions as much as possible in their lives. For example, people with food allergies should no longer consume related allergens; people who are allergic to environmental factors can stay away from specific environments or protect themselves by wearing masks; people who are allergic to drugs should not only inform the doctor of their previous history of drug allergies every time they visit the doctor, but also be careful not to use drugs containing the same ingredients unless necessary.

In summary, for the diagnosis and treatment of chronic urticaria, we must not only have confidence, but also patience, pay attention to adjusting the lifestyle according to the characteristics of our own condition, and take medication on time according to the treatment plan prescribed by the doctor. I hope that my friends can get rid of the troubles of urticaria as soon as possible, without pain or itching, and be happy!

References

[1] Urticaria Research Center of the Chinese Society of Dermatology and Venereology. Chinese Guidelines for the Diagnosis and Treatment of Urticaria (2022 Edition). Chinese Journal of Dermatology, 2022, 55(12):1041-1047.