Cholinergic urticaria (CU) presents with tiny very itchy wheals and small bumps on a reddish background.It is a type of physical urticaria (or hives) that appears when a person is sweating or their core body temperature increases. Symptoms
Cholinergic urticaria typically presents with a number of small, short-lasting hives but may also involve cutaneous inflammation (wheals) and pain which develops usually in response to exercise, bathing, staying in a heated environment, or emotional stress. Although the symptoms subside rapidly, commonly within 1 hour, cholinergic urticaria may significantly impair quality of life, especially in relation to sporting activities. Causes
Sweat hypersensitivity
Acquired anhidrosis and/or hypohidrosis
Idiopathic
Opioid use
Cholinesterase inhibitors

Subtypes
Sweat hypersensitivity
This subtype of CU refers to those who are hypersensitive to their own sweat. Diagnosis
Diagnosis is made by injecting autologous (the persons own) sweat into the skin. Features
The hives are observed to coincide with perspiration points of sweating. Pathophysiology
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. Treatment
Proposed first-line treatment: Rapid desensitization protocol using autologous sweat. Non-pharmacological treatment: Forced perspiration by excessive body warming (hot bath or exercise) used daily may reduce the symptoms through exhaustion of inflammatory mediators. This non-pharmacological treatment is contraindicated in those with CU as a result of hypohidrosis (see below).
Pyromania is an impulse control disorder in which individuals repeatedly fail to resist impulses to deliberately start fires, to relieve some tension or for instant gratification. The term pyromania comes from the Greek word πῦρ (pyr, fire). Pyromania is distinct from arson, the deliberate setting of fires for personal, monetary or political gain. Pyromaniacs start fires to release anxiety and tension, or for arousal. Other impulse disorders include kleptomania and intermittent explosive disorder. There are specific symptoms that separate pyromaniacs from those who start fires for criminal purposes or due to emotional motivations not specifically related to fire. Someone with this disorder deliberately and purposely sets fires on more than one occasion, and before the act of lighting the fire the person usually experiences tension and an emotional buildup. When around fires, a person with pyromania gains intense interest or fascination and may also experience pleasure, gratification or relief. Another long term contributor often linked with pyromania is the buildup of stress. When studying the lifestyle of someone with pyromania, a buildup of stress and emotion is often evident and this is seen in teens attitudes towards friends and family. At times it is difficult to distinguish the difference between pyromania and experimentation in childhood because both involve pleasure from the fire. Classification
ICD
The World Health Organizations International Classification of Diseases (11th Revision) ICD-11, regarded as the global standard, was released in June 2018 and came into full effect from January 2022.