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Cholinergic urticaria | |
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CU on the volar aspect of the forearm | |
Specialty | Dermatology |
Symptoms | Tiny "itchy" wheals and small papular bumps on a reddish background. [1] |
Causes | Unclear (triggered by heat) |
Treatment | Medications, sweat therapy |
Cholinergic urticaria (CholU, CU) is a form of hives (urticaria) that is triggered by an elevation in body temperature, breaking a sweat, or exposure to heat. It is also sometimes called exercise-induced urticaria or heat hives. The condition is caused by an overreaction of the immune system to the release of histamine and other chemicals in response to the increase in body temperature. This results in the characteristic red, itchy, and sometimes raised bumps or welts on the skin that are associated with hives.
Cholinergic urticaria typically presents with a number of small papular hives all over the body, that involve cutaneous inflammation (wheals) and severe nerve pain, which usually develops in response to exercise, bathing, staying in a heated environment, spicy foods, or emotional stress. [2] [3] The symptoms subside and manifest rapidly on and off throughout the day with no notice. Cholinergic urticaria may significantly impair quality of life, especially in relation to normal day to day activities. It is caused by an overreaction of the immune system to the release of histamine, mast cells, and other chemicals in response to the small nerve fibers throughout the body due to the increase in body temperature being allergic to sweat. [4]
This subtype of CU refers to those who are hypersensitive to their own sweat.
Diagnosis is made by injecting autologous (the person's own) sweat into the skin. [5]
The hives are observed to coincide with perspiration points of sweating. [6]
Tanaka et al. found that the sweat hyper-sensitivities of CU and atopic dermatitis seem to be virtually the same, and therefore, the sweat-induced histamine release from basophils may also be mediated by a specific IgE for sweat in atopic dermatitis as well as CU. [6]
This subtype of CU refers to those who have abnormally reduced sweating. Forced perspiration by excessive body warming (hot bath or exercise) used daily may reduce the symptoms through exhaustion of inflammatory mediators. [7]
Sweat is readily visualized by a topical indicator such as iodinated starch or sodium alizarin sulphonate. Both undergo a dramatic colour change when moistened by sweat. A thermoregulatory sweat test evaluates the body's response to a thermal stimulus by inducing sweating through the use of a hot box ⁄ room, thermal blanket or exercise. Failure of the topical indicator to undergo a colour change during thermoregulatory sweat testing can indicate anhidrosis and/or hypohidrosis (see Minor test). [14]
A skin biopsy may reveal cellular infiltrates in sweat glands or ducts. [6]
Severe heat intolerance (e.g., nausea, dizziness, and headache), and tingling, pricking, pinchy or burning pain over the entire body on exposure to hot environments or prolonged exercise which improve after cooling the body. Occurs in the absence of any causative skin, metabolic, or neurological disorders. [15]
[16] The wheals, hypohidrosis, and pain seems to result from the low expression levels of acetylcholinesterase (AchE) and cholinergic receptor, muscarinic 3 (CHRM3) in the eccrine gland epithelial cells.
Elevated expression levels of CCL2/MCP-1, CCL5/RANTES and CCL17/TARC which result in chemoattracted CD4+ and CD8+ T cell populations to the surrounding area may be responsible for exerting a downmodulatory effect on the AchE and CHRM3 expressions.
Corticosteroid inhibits the expressions of CCL2/MCP-1, CCL5/RANTES and CCL17/TARC. This further support the notion that CCL2/MCP-1, CCL5/RANTES and CCL17/TARC play a crucial role.
Unknown or unclassified at this time. This represents those who do not fall under any of the above categories.
Though overall research is limited, various studies indicate that CU is relatively common across populations with prevalence rates reportedly ranging from 5% to 20% (depending on locale, race, and age). [19] [20] [21] The condition is more common in young adults, and prevalence appears to peak in adults aged 26–28 (up to 20%). [19] The vast majority of cases are reported to be mild, and proportionally few individuals seek medical attention regarding the condition.
Cholinergic urticaria was first described by Duke [22] in 1924 as "urticaria calorica". The term cholinergic is derived from the finding that hives similar to those of CU can be evoked using cholinergic agonists (e.g. methacholine).
Perspiration, also known as sweat, is the fluid secreted by sweat glands in the skin of mammals.
Hematidrosis, also called hematohidrosis, haematidrosis, hemidrosis and blood sweat, is a very rare condition in which a human sweats blood. The term is from Ancient Greek haîma/haímatos, meaning blood, and hīdrṓs, meaning sweat.
Hives, also known as urticaria, is a kind of skin rash with red and/or flesh-colored, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and do not leave any long-lasting skin change. Fewer than 5% of cases last for more than six weeks. The condition frequently recurs.
Miliaria, commonly known as heat rash, sweat rash, or prickly heat, is a skin disease marked by small, itchy rashes due to sweat trapped under the skin by clogged sweat-gland ducts. Miliaria is a common ailment in hot and humid conditions, such as in the tropics and during the summer. Although it affects people of all ages, it is especially common in children and infants due to their underdeveloped sweat glands.
Cold urticaria is a disorder in which large red welts called hives (urticaria) form on the skin after exposure to a cold stimulus. The hives are usually itchy and often the hands, feet and other parts of the body will become itchy and swollen as well. Hives vary in size from about 7 mm in diameter to as big as about 27 mm or larger.
Dermatographic urticaria is a skin disorder and one of the most common types of urticaria, affecting 2–5% of the population.
Aquagenic pruritus is a skin condition characterized by the development of severe, intense, prickling-like epidermal itching without observable skin lesions and evoked by contact with water.
Urticaria pigmentosa (also known as generalized eruption of cutaneous mastocytosis (childhood type) ) is the most common form of cutaneous mastocytosis. It is a rare disease caused by excessive numbers of mast cells in the skin that produce hives or lesions on the skin when irritated.
Physical urticaria is a distinct subgroup of urticaria (hives) that are induced by an exogenous physical stimulus rather than occurring spontaneously. There are seven subcategories that are recognized as independent diseases. Physical urticaria is known to be painful, itchy and physically unappealing; it can recur for months to years.
CCL17 is a powerful chemokine produced in the thymus and by antigen-presenting cells like dendritic cells, macrophages, and monocytes. CCL17 plays a complex role in cancer. It attracts T-regulatory cells allowing for some cancers to evade an immune response. However, in other cancers, such as melanoma, an increase in CCL17 is linked to an improved outcome. CCL17 has also been linked to autoimmune and allergic diseases.
Pitted keratolysis is a bacterial skin infection of the foot. The infection is characterized by craterlike pits on the sole of the feet and toes, particularly weight-bearing areas.
Hypohidrosis is a medical condition in which a person exhibits diminished sweating in response to appropriate stimuli. In contrast with hyperhidrosis, which is a socially troubling yet often benign condition, the consequences of untreated hypohidrosis include hyperthermia, heat stroke and death. An extreme case of hypohidrosis in which there is a complete absence of sweating and the skin is dry is termed anhidrosis. The condition is also known as adiaphoresis, ischidrosis, oligidria, oligohidrosis and sweating deficiency.
Solar urticaria (SU) is a rare condition in which exposure to ultraviolet or UV radiation, or sometimes even visible light, induces a case of urticaria or hives that can appear in both covered and uncovered areas of the skin. It is classified as a type of physical urticaria. The classification of disease types is somewhat controversial. One classification system distinguished various types of SU based on the wavelength of the radiation that causes the breakout; another classification system is based on the type of allergen that initiates a breakout.
Aquagenic urticaria, also known as water allergy and water urticaria, is a form of physical urticaria in which hives develop on the skin after contact with water, regardless of its temperature. The condition typically results from contact with water of any type, temperature or additive.
Ross' syndrome consists of Adie's syndrome plus segmental anhidrosis.
Idiopathic pure sudomotor failure (IPSF) is the most common cause of a rare disorder known as acquired idiopathic generalized anhidrosis (AIGA), a clinical syndrome characterized by generalized decrease or absence of sweating without other autonomic and somatic nervous dysfunctions and without persistent organic cutaneous lesions.
Acquired idiopathic generalized anhidrosis (AIGA) is characterized by generalized absence of sweating without other autonomic and neurologic dysfunction. Other symptoms include facial flushing, headaches, disorientation, lassitude, hyperthermia, weakness, and palpitations.
Chronic spontaneous urticaria(CSU) also known as Chronic idiopathic urticaria(CIU) is defined by the presence of wheals, angioedema, or both for more than six weeks. The most common symptoms of chronic spontaneous urticaria are angioedema and hives that are accompanied by itchiness.
A sweat allergy is the exacerbation of atopic dermatitis associated with an elevated body temperature and resulting increases in the production of sweat. It appears as small reddish welts that become visible in response to increased temperature and resulting production of sweat. It can affect all ages. Sweating can trigger intense itching or cholinergic urticaria. The protein MGL_1304 secreted by mycobiota (fungi) present on the skin such as Malassezia globosa acts as a histamine or antigen. People can be desensitized using their own samples of sweat that have been purified that contains small amounts of the allergen. The allergy is not due to the sweat itself but instead to an allergy-producing protein secreted by microorganisms found on the skin.
Autoimmune urticaria, also known as chronic autoimmune urticaria, is a type of chronic urticaria characterized by the presence of autoantibodies in the patient's immune system that target the body's own mast cells, leading to episodes of hives (urticaria). This immunologically distinct type of urticaria is considered autoimmune because the immune system, which normally protects the body from foreign organisms, mistakenly attacks the body's own cells, causing inflammation and other symptoms.