What is Cholinergic Urticaria (CU)?
Cholinergic urticaria (CU) is a type of physical urticaria which significantly appears when a person sweats profusely. Although the kind of stimulus may be a considered as heat, the hives are caused due to sweating. Cholinergic urticaria is a common disorder that affects the immune system and is often categorized by catastrophic skin reaction to exercise, heat or emotional stress. Cholinergic urticaria symptoms may involve the appearance of small eruptions of skin that are known as hives. The borders of such lesions are well-defined and they usually have a pale or irregular center. The lesion is sometime surrounded by red patches and they are caused due to the intense scratching. Rarely, cholinergic urticaria may be linked with some symptoms like fever or heavy breathing.
The symptoms that are developed with this kind of urticaria may be due to the reaction that the immune system is undergoing. It may be due to the antibodies (like IgE) reaction when the body is subjected to certain antigens. This further helps in developing the symptoms that relate to cholinergic urticaria.
What Are The Causes of Cholinergic Urticaria (CU)?
If you notice something that appears to be similar to a heat rash or you are experiencing itchiness when you exercise, eat spicy food or sit for some time in warmer surroundings, it is advisable to visit a doctor. Commonly known as heat hives, cholinergic urticaria should be treated in the early stages.
Any individual may have a tendency to develop cholinergic urticaria when the body is subjected to various activities that involves increased body temperatures. Few examples of activities that can cause Cholinergic Urticaria are as follows:
- Anxiety or stress
- Taking a bath or a hot shower
- Consuming spicy or pungent foods
- Indulging in physical activities or exercises.
- Emotional stress and associated responses
- Changing the climatic surroundings while moving from cool to hot environment.
Types of Cholinergic Urticaria
Cholinergic urticaria can be categorized into major 4 subtypes:
- Cholinergic hives with poral occlusion
- Cholinergic hives with acquired, generalized hypohidrosis
- Cholinergic hives with sweat allergy
- Idiopathic cholinergic hives
Risk Factors for Cholinergic Urticaria
People who have increased risk of suffering from cholinergic urticaria may involve:
- People who are already suffering from general chronic urticaria
- People who are allergic to various conditions like rhinitis, atopic dermatitis and asthma.
Cholinergic urticaria is seen in both women and men, but is commonly seen in men. The condition primarily appears in people who belong to the age group of 10 to 30 years and it stays for a few years before it fades away or becomes less severe. The natural course of its appearance may vary from individual to individual, but many patients seem to experience slower resolution.
Signs and Symptoms of Cholinergic Urticaria
Those with Cholinergic Urticaria do not show any symptoms when their body is not exposed to a stimulus or increasing temperatures. These individuals appear to be healthy and can function normally as well. Their body exhibits such symptoms only when they are exposed to heat or its stimulus. In this case, an individual starts to feel itchy when he or she is exposed to the changing heat environment or is emotionally stressed. Once the itching starts in an area, it eventually spreads all over the body. Some localized areas like legs, face, back and chest may show significant appearance of symptoms when they are exposed.
The sensation never stops or comes down until the person finds a way to cool down the body temperatures. Other associated symptoms are as follows:
- Intense itching, burning sensation or skin stinging may be seen and worse. They follow a particular pattern of appearance and can be described as bee stinging or fire ant biting.
- Appearance of red flushes on skin.
- Appearance of smaller hives which disappear when the body temperature cools down. These eruptions can also be termed as heat rash and will differ from the ordinary heat rash that is seen in summers. The ordinary rashes are called Miliaria Rubra, which can be a cause of sweat pore blockage. However, the latter can be cured within a few weeks, but the former stays for quite a long time.
- Appearance of tiny wheals on the skin where it is exposed to the sun.
- The ability to sweat less or appearance of General anhidrosis. People who suffer from cholinergic urticaria find it difficult to sweat and when the person sweats, it gives rise to skin eruptions.
Cholinergic Urticaria Symptoms in Children
If the symptoms of cholinergic urticaria are seen in children, it is advisable to rely on an allergist rather than a dermatologist. An allergist will be more familiar with the condition than a dermatologist.
Diagnosis of Cholinergic Urticaria
Certain reports have shown that the sufferers of chronic urticaria often have cholinergic urticaria but the morphology is entirely different. Aquagenic urticaria is observed when the skin is subjected to cold water or hot water. Nevertheless, if the patient’s skin is exposed to tap water, the appeared lesions may be similar to cholinergic urticaria. When the patient shows symptoms of adrenergic urticaria, the rashes are bordered by vasoconstriction. Patients, who have been reported with one type of urticaria, often have other associated urticaria that is generated by a similar stimulus. Conditions like pressure urticaria, Aquagenic urticaria and cold urticaria may be associated with cholinergic urticaria.
Treatment for Cholinergic Urticaria
The exact cure for cholinergic urticaria is not yet known. The researchers and the doctors have not yet diagnosed the mechanisms that lead to the skin eruptions. Therefore, they are currently focusing on managing and treating the symptoms of this disorder at the earliest.
Medications For Cholinergic Urticaria
Antihistamines are a type of drugs or agents that prevent or inhibit the histamine release in the body. When the body is attacked by cholinergic urticaria, it releases histamine. This causes a feeling of itchiness in the body when the hives are formed.
Commonly Used Antihistamines For Treating Cholinergic Urticaria May Include:
- Desloratadine (Clarinex)
- Allegra (Fexofenadine)
- Cetirizine (Zyrtec)
- Loratadine (Claritin)
- Pepcid and Ranitidine.
The above mentioned antihistamines can be prescribed for alleviating the cholinergic urticaria symptoms. The results may, however, vary from person to person, but they show some dramatic results in curing the disease with an amount of time. Whilst this is the case observed in certain individuals, some people do not show any changes in the symptoms at all.
Danazol: The occasional treatment of cholinergic urticaria can be done using steroids. These are usually used when the symptoms are severe. Some shows mixed results when the anabolic steroids are consumed in such a condition. In some individuals the symptoms reappear and in some they permanently vanish after prolonged consumption of drugs.
Prednisone: It is a kind of corticosteroid that is used for treating the diseases related to the immune system. It is significantly prescribed for people who are suffering from cholinergic urticaria. This medication has a tendency of suppressing the effect of such disease on the immune system, which means that it lowers the response of the immune system.
UVB Light Therapy or Sunlight Therapy for Cholinergic Urticaria
Cholinergic urticaria is sometimes treated using the UVB light therapy. There are instances when the symptoms were permanently eliminated from the body when the treatment was ongoing. Skin specialists or dermatologists often treat this disease. There are some patients who have also reported re-appearance of symptoms once the treatment was permanently ceased.
However, the sufferer may have an increased risk of developing cancer and other factors along with skin aging when they are exposed to UVB light consistently.
Lifestyle Modifications for Cholinergic Urticaria
Cholinergic urticaria can be managed in a natural way by following certain healthy habits as follows:
- Using various relaxation techniques to keep the mind cool and away from stressful situations. This will help in keeping away the emotional stresses that can lead to an increased risk of lesion development.
- Using ice packs and cooling sprays that can resolve the reactions which may be erupting.
- Avoiding consumption of illicit drugs that can trigger the symptoms of cholinergic urticaria.
- Keeping away from situations that can generate hives or cool the body rapidly after transitioning from a hotter environment.
- Keeping the body cool by wearing the right clothes that will keep the skin aerated.
- Changing the dietary habits. Avoiding consumption of spicy foods or those which increase the body temperature.
Alternative Therapy for Cholinergic Urticaria
Sweat Therapy or Exercise: There are individuals who practice doing exercise just to keep the level of symptoms down or prevent their attacks. The basic idea behind doing this is compelling; the body to attack and at the same time perspires more. This enables the body to release the histamines and indulge in temporarily bringing down its level and reduce the appearance of lesions as well. This approach shows some significant results in treating the mild versions of cholinergic urticaria and when continued, it can help in getting rid of the problem permanently.
- DermNet NZ. (2021). Cholinergic Urticaria. https://dermnetnz.org/topics/cholinergic-urticaria