Grovers disease (GD) is a polymorphic, pruritic, papulovesicular dermatosis characterized histologically by acantholysis: 529  with or without dyskeratosis. Once confirmed, most cases of Grovers disease last six to twelve months, which is why it was originally called "transient". However it may last much longer. Nevertheless, it is not to be confused with relapsing linear acantholytic dermatosis. Signs and symptoms
Grovers disease often starts quite suddenly. There are intensely itchy spots on the central back, mid chest and occasionally elsewhere. Frequently, it follows sweating or some unexpected heat stress. The itchy eruption lasts an average of 10–12 months. It is characterized by papules and papulovesicles with excoriations occurring on the chest, back, lower sternum, arms, and thighs. The papules are most commonly found on the mid chest. Sometimes the features of Grovers are found in people who do not itch or have a conspicuous rash. Most of the people with Grovers who visit a dermatologist, however, itch a lot. Cause
The cause of Grovers disease is unknown. Suspected triggers of disease activity include heat and sweating, sunlight, and adverse reaction to medications: 24  as well as ionizing radiation, end-stage renal disease/hemodialysis, and mechanical irritation or prolonged bed rest. Some cases of Grovers disease have been associated with medications such as sulfadoxine-pyrimethamine, ribavirin, cetuximab, and interleukin-4 [1,8-15]. One series of 300 patients with Grovers disease reported an association with other coexisting dermatoses including atopic dermatitis, contact dermatitis, and xerosis cutis. Finally, smaller series have detailed an association with pyoderma gangrenosum, bacterial and viral infections, and occasionally, malignancies.
Bigeminy is a cardiac arrhythmia in which there is a single ectopic beat, or irregular heartbeat, following each regular heartbeat. Most often this is due to ectopic beats occurring so frequently that there is one after each sinus beat, or normal heartbeat. The two beats are figuratively similar to two twins (hence bi- + gemini). For example, in ventricular bigeminy, a sinus beat is shortly followed by a premature ventricular contraction (PVC), a pause, another normal beat, and then another PVC. In atrial bigeminy, the other "twin" is a premature atrial contraction (PAC). Cause
After any PVC there is a pause that can lead to the development of bigeminy. A PVC wavefront often encounters a refractory AV node that does not conduct the wavefront retrograde. Thus the atrium is not depolarized and the sinus node is not reset. Since the sinus P wave to PVC interval is less than the normal P–P interval, the interval between the PVC and the next P wave is prolonged to equal the normal time elapsed during two P–P intervals. This is called a "compensatory" pause. The pause after the PVC leads to a longer recovery time, which is associated with a higher likelihood of myocardium being in different stages of repolarization. This then allows for re-entrant circuits and sets up the ventricle for another PVC after the next sinus beat.