Cholinergic Urticaria

Key Points
Fairly common form of physical urticaria (Hives)
Caused by sweating or heat
Consists of small welts surrounded by bright red flares on the skin of the area

Cholinergic Urticaria is a common form of hives, caused by sweating. The rash consists of very small welts surrounded by bright red flares on the skin of the area. The rash will appear rapidly, and can last up to an hour or more. It may be preceded by itching, burning and warm sensations. Upon formation, the rash is often very itchy, and can form anywhere on the body except the palms and soles of the feet. Severe cases may be accompanied by headaches, salivation, palpitations, shortness of breath, wheezing, cramps and diarrhea. Very rarely, affected persons can have anaphylactic reactions.

Cholinergic Urticaria is more common in men, though it can affect anyone. It typically occurs for a number of years, slowly becoming less severe and often disappearing altogether. Affected persons who suffer from chronic urticaria (generalized chronic hives), or persons with allergic conditions such as asthma, rhinitis, or atopic Dermatitis are more likely to suffer from cholinergic urticaria.

Differential Diagnosis (Other conditions with similar appearance)

Urticaria (Various types)

Diagnosis
Key Points
Diagnosis based on skin appearance
Other tests, including Injections or causing sweating in a clinical setting, confirm diagnosis

Diagnosis of Cholinergic Urticaria is generally based on appearance of the affected area, then confirmed by clinical testing, including exercise under the supervision of health care professionals or Injections of certain chemicals to reproduce a reaction.

Treatment
Rapid cooling may prevent attacks
Goal of treatment is to control symptoms
Avoiding activities or situations which trigger attacks is recommended.
OTC Options: Antihistamines

The best treatment for Cholinergic Urticaria is to avoid activities or situations which bring on attacks of the condition. If unable to avoid a situation in which an attack might occur, rapid cooling may in some cases prevent the flare-up. The most common treatment is the regular usage of oral Antihistamines, which prevent the reaction from occurring. In some cases, beta-blockers have been used to the same end, with some effectiveness.