Differential Diagnosis for Penile Erythema in an Infant
Single Most Likely Diagnosis
- Irritant Dermatitis: This is the most common cause of penile erythema in infants, often due to irritation from urine or feces. The location and appearance of the erythema, along with the age of the patient, make this a highly plausible diagnosis.
Other Likely Diagnoses
- Candidiasis: Given the warm, moist environment of a diapered area, candida infections are common. Penile erythema could be a manifestation of such an infection, especially if there's a history of oral thrush or recent antibiotic use.
- Eczema (Atopic Dermatitis): Infants with a family history of atopy are at higher risk. Eczema can present with erythema and is often seen in areas prone to moisture, such as the diaper area.
- Contact Dermatitis (Allergic): This could be due to an allergic reaction to components of diapers, wipes, or other products coming into contact with the infant's skin.
Do Not Miss Diagnoses
- Balanitis: Inflammation of the glans penis, which can be caused by infection (bacterial, viral, or fungal) or other irritants. It's crucial to identify and treat the underlying cause to prevent complications.
- Urinary Tract Infection (UTI): Although less common in male infants, UTIs can cause irritation and erythema of the genital area. Given the potential for serious complications, such as pyelonephritis or sepsis, UTIs must be considered.
- Sexually Transmitted Infections (STIs): In the case of non-accidental injury or sexual abuse, STIs could present with penile erythema. This diagnosis is critical to consider for the infant's safety and well-being.
Rare Diagnoses
- Psoriasis: Although rare in infants, psoriasis can cause erythematous plaques. The penile area can be involved, and it's essential to consider this diagnosis if other common causes have been ruled out.
- Lichen Sclerosus: A rare condition that can cause thinning and whitening of the skin, sometimes presenting with erythema. It's more commonly seen in prepubertal girls but can occur in boys.
- Zinc Deficiency: Can lead to skin lesions and erythema, among other symptoms. This would be an unusual cause but should be considered in infants with dietary deficiencies or malabsorption issues.