Common Perianal Dermatoses and Pigmented Skin Lesions in Children

In pediatric clinical practice, skin findings in the perianal region and various pigmented lesions on the body are frequent points of evaluation. While many of these findings are benign or related to common irritants, some require careful differentiation to rule out serious conditions such as infection, genetic syndromes, or even physical abuse. This article provides a clinical overview of the most common perianal dermatoses and pigmented skin lesions encountered in infants and children.

Perianal Dermatoses

Perianal skin irritation is a common complaint in pediatric patients, ranging from newborns to school-aged children. The presentation—specifically whether the rash involves the skinfolds—is a critical diagnostic clue.

Irritant Contact Dermatitis

Irritant contact dermatitis is the most common perianal dermatosis seen in infants. It is typically caused by skin breakdown due to prolonged exposure to urine or stool. A hallmark of this condition is that the erythematous rash spares the skinfolds. Management is straightforward and involves the application of topical barrier ointments, such as zinc oxide or petrolatum.

Candida Diaper Dermatitis

The second most common cause of perianal rash in infants is Candida diaper dermatitis. Unlike irritant dermatitis, Candida infections do not spare the skinfolds. Clinically, it presents as "beefy red," confluent plaques that often feature characteristic satellite lesions. This condition requires treatment with topical antifungal agents, such as nystatin.

Perianal Streptococcus

While the previous two conditions are primarily seen in infants, perianal streptococcus is frequently observed in school-aged children in addition to infants. This infection presents as a sharply demarcated, red perianal rash. Patients often experience associated pruritus (itching) and pain, which may lead to constipation or blood-streaked stools if the child begins withholding stool to avoid the pain of defecation. Diagnosis can be confirmed via a perianal bacterial culture, and treatment involves oral $\beta$-lactam antibiotics.