Intussusception occurs when a portion of the bowel is pushed into another portion. It most commonly affects children under the age of two. Red currant jelly stools (stool mixed with blood and mucus) vomiting, and pain are common symptoms. Red currant jelly stools are a hallmark of intussusception. Pyloric stenosis generally causes reflux post feeding and encopresis affects children who have already been toilet trained. Hernias are rare in young patients. Encopresis refers to involuntary fecal soiling in children who are already toilet-trained, and does not involve abnormal stool, such as currant-jelly characterization.

Exercise intolerance is a typical clinical finding in pediatric patients with aortic stenosis. This condition may present with any of the other symptoms but mania, excessive sweating, and epigastric pain are not directly associated with aortic insufficiency in this population.

Parvovirus B-19 causes fifth's disease, sometimes referred to as "slapped cheek syndrome," due to the bright-red cheeks that often present with the infection. Scarlet fever is caused by group A streptococcus infection. Roseola infantum is caused by either human herpesvirus 6 or human herpesvirus 7. Rubeola, or measles, is caused by the measles virus.

Varicella, caused by an infection with the varicella zoster virus, has an incubation period of 10-21 days. 

The most common cause of hand, foot, and mouth disease in the United States is coxsackievirus A16. Enterovirus 71 can also cause hand, foot, and mouth disease, though it is a less common etiology. Parvovirus b19 causes Fifth disease, sometimes referred to as "slapped cheek syndrome." Human herpesvirus 6 is one of two viruses that cause roseola infantum.

Retinoblastoma is the most common form of ocular cancer in children. It is derived from developing retinal cells. The most common symptoms are a white or yellow light reflex (also known as leukocoria), diminished pupillary reflex, crossing of the eyes, impaired vision, and bulging of the affected eye. A cataract may also cause the pupil to appear white or to produce a white or yellow light reflex, but it will not cause bulging of the eye.

A pinguecula is a fatty deposit on the sclera which will not alter the red-light reflex, and a hordeolum is outside the eye itself: it is an infection of a hair follicle of the eyelid, also known as a stye. 

A preterm infant cannot conserve heat due to several reasons. The infant has a lack of subcutaneous fat, has a large surface area relative to their body weight, a lack of glucose reserves, and a lack of brown fat - which is a unique type of fat that is capable of generating a greater amount of heat than just ordinary fat. 

In 21-hydroxylase deficiency, cortisol production is reduced, which in turn causes adrenocorticotropic hormone (ACTH) to increase. The precursors for the cortisol are then shunted into androgen production since these are steroids, and are thus derived from cholesterol.

Newborns should be placed on their back, in their crib, with nothing else when put to sleep. The crib may contain a fitted sheet or a light blanket. Crib pads, pillows, and stuffed animals are not advised because they may interfere with the child's ability to breathe.

Typically, the digestive system of a 2-day-old infant can only accommodate 15-30 milliliters of formula comfortably. The infant's stomach will grow considerably over the coming weeks. Frequent spitting up could be due to overfeeding. Before switching formula brands, try decreasing the amount fed at each feeding. Increasing the frequency of feedings may add to this problem. Another possibility, that the infant is feeding too fast, may be corrected by using a "slow-flow" instead of a "soft" or "standard" nipple. "Soft" nipples may be helpful in infants with poor suck or latch. While feeding and directly afterwards, it is advised to keep the infant in a semi-upright position.