What denotes a lack of satellite lesions in diaper rash?

A lack of satellite lesions in a diaper rash is indicative of contact dermatitis. Contact dermatitis occurs as a reaction to irritation from urine, feces, or from the diaper material itself, rather than an infectious process.

In cases of Candida infection, satellite lesions, which are small spots of rash that appear in the skin folds away from the main rash area, are commonly seen due to the yeast overgrowth, particularly in warm, moist areas. Therefore, this would not align with the characteristics of contact dermatitis.

Psoriasis, although it can occur in diaper areas, typically has a distinct presentation that can include well-defined plaques covered with silvery scales and is not commonly associated with the diaper area in infants.

Impetigo is a bacterial infection that would also present with different features, such as crusting pustules and marked redness, rather than the typically irritated skin of contact dermatitis.

Thus, the absence of satellite lesions is consistent with contact dermatitis, making it the correct answer.