The University of Maryland Medical Center defines pathological gambling as "being unable to resist impulses to gamble, which can lead to severe personal or social consequences".Most other definitions of problem gambling can usually be simplified to any gambling that causes harm to the gambler or someone else in any way; however, these definitions are usually coupled with descriptions of the type of harm or the use of diagnostic criteria. The DSM-V has since reclassified pathological gambling as "gambling disorder" and has listed the disorder under substance-related and addictive disorders rather than impulse-control disorders. This is due to the symptomatology of the disorder resembling an addiction not dissimilar to that of a substance use disorder.
A biopsy of the lesions will show extravasated erythrocytes within dermal papillae and dyskeratotic cells within the dermis.A set of validated diagnostic criteria for pityriasis rosea is as follows:
A patient is diagnosed as having pityriasis rosea if:

On at least one occasion or clinical encounter, the patient has all the essential clinical features and at least one of the optional clinical features, and
On all occasions or clinical encounters related to the rash, the patient does not have any of the exclusional clinical features.The essential clinical features are the following:
Discrete circular or oval lesions,
Scaling on most lesions, and
Peripheral collarette scaling with central clearance on at least two lesions.The optional clinical features are the following:
Truncal and proximal limb distribution, with less than 10% of lesions distal to mid-upper-arm and mid-thigh,
Orientation of most lesions along skin cleavage lines, and
A herald patch (not necessarily the largest) appearing at least two days before eruption of other lesions, from history of the patient or from clinical observation.The exclusional clinical features are the following:
Multiple small vesicles at the centre of two or more lesions,
Two or more lesions on palmar or plantar skin surfaces, and
Clinical or serological evidence of secondary syphilis. Treatment
The condition usually resolves on its own, and treatment is not required. Oral antihistamines or topical steroids may be used to decrease itching. Steroids do provide relief from itching, and improve the appearance of the rash, but they also cause the new skin that forms (after the rash subsides) to take longer to match the surrounding skin color.