The diagnosis of diaper rash is made clinically. Laboratory testing can help us in excluding other diseases of the skin.
Candidiasis is suspected when intertiginous areas are involved or when the rash fails to respond to symptomatic treatment. Potassium hydroxide (KOH) scrapings can show pseudohyphae in suspected cases of candidiasis.
The treatment of diaper rash consists of the following  .
With the improvement of diaper hygiene, diaper rash usually resolves without any complications. Diaper rash due to Candida albicans may take up to 3 weeks to resolve.
Every child usually has at least one episode of diaper rash in his or her life. The incidence of diaper rash is around 4-35% in the first 2 years of life. The peak incidence occurs at 7-12 months of age.
A decrease in incidence is seen after toilet training of child which occur at 2 years of age. Moreover, the incidence is lower in breast fed babies. The number of incidents are far greater than the cases reported. The cases of atopic dermatitis are more common in African American population.
Oral thrush is also associated with a higher incidence of diaper rash.
Diaper rash occurs due to interaction of a number of factors. These include moisture, friction, urine and feces, lack of air exposure, the presence of microorganisms and the presence of dye and irritant substances. The creases and folds of the skin lead to difficulty in cleaning of the diaper area and are hence more often involved.
Due to excessive hydration, there is softening of the stratum corneum of the skin. This leads to progressive break down of intercellular lipids. Since stratum corneum is a protective layer, this breakdown will lead to the entry of microorganisms in the skin.
Furthermore, when the fecal and urinary ammonia mix in the diaper, it will lead to decreased hydrogen ion concentration causing a further increase in the pH of the skin. This further augments the cycle of breakdown of the skin lipid layer.
Contrary to the popular belief, ammonia itself does not cause dermatitis. When the baby has diarrhea, excessive amounts of enzymes such as proteases and lipases are excreted in the stool. These fecal enzymes also increase the hydration of the skin and its permeability to bile salts, which also act as skin irritants. The alkaline urine causes activation of fecal lipases, ureases, and proteases which further increases the damage to skin  .
Superabsorbent diapers that contain certain dyes are suspected to cause allergic contact dermatitis. Secondary staphylococcus and streptococcus infections can also further complicate the irritant diaper rash. When the skin is immunocompromised, it will predispose to the development of Candida infections.
Diaper rash or diaper dermatitis is an inflammatory condition of the skin that usually presents with itching and rash in region the diapers are worn . Usually every baby has diaper rash once in his or her life time. Frequent stools and improper use of diapers can lead to repetitive episodes of diaper rash .
The high alkaline pH and excessive hydration of the skin lead to breaking of its lipid layer. The mixing of fecal protease and lipase also further increases the pH. In case of secondary bacterial infection, the rash is often accompanied by fever; whereas in case of Candida infection, oral thrush is also often present  . Diaper rash usually resolves within 3 days.