Diagnostic and statistical manual
PTSD was classified as an anxiety disorder in the DSM-IV, but has since been reclassified as a "trauma- and stressor-related disorder" in the DSM-5. The DSM-5 diagnostic criteria for PTSD include four symptom clusters: re-experiencing, avoidance, negative alterations in cognition/mood, and alterations in arousal and reactivity. International classification of diseases
The International Classification of Diseases and Related Health Problems 10 (ICD-10) classifies PTSD under "Reaction to severe stress, and adjustment disorders." The ICD-10 criteria for PTSD include re-experiencing, avoidance, and either increased reactivity or inability to recall certain details related to the event.The ICD-11 diagnostic description for PTSD contains three components or symptom groups (1) re-experiencing, (2) avoidance, and (3) heightened sense of threat. ICD-11 no longer includes verbal thoughts about the traumatic event as a symptom. There is a predicted lower rate of diagnosed PTSD using ICD-11 compared to ICD10 or DSM-5. ICD-11 also proposes identifying a distinct group with complex post-traumatic stress disorder (CPTSD), who have more often experienced several or sustained traumas and have greater functional impairment than those with PTSD. Differential diagnosis
A diagnosis of PTSD requires that the person has been exposed to an extreme stressor. Any stressor can result in a diagnosis of adjustment disorder and it is an appropriate diagnosis for a stressor and a symptom pattern that does not meet the criteria for PTSD. The symptom pattern for acute stress disorder must occur and be resolved within four weeks of the trauma.
Trichilemmal carcinoma  is a cutaneous condition reported to arise on sun-exposed areas, most commonly the face and ears. : 674

See also
Trichilemmoma
Skin lesionA similar tumor, although in the nail bed, is called onycholemmal. References


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