Is keratosis pilaris (KP) common in infants?

Keratosis Pilaris in Infants

Yes, keratosis pilaris is common in infants, with some variants appearing as early as before 18 months of age. 1

Clinical Presentation in Infants

Keratosis pilaris (KP) in infants presents as:

• Small, folliculocentric keratotic papules that give the skin a stippled or "gooseflesh" appearance
• Commonly affects the extensor aspects of upper arms, upper legs, and buttocks
• May involve the cheeks in infants and young children
• Variable degrees of surrounding erythema may be present
• Usually asymptomatic, with concerns primarily being cosmetic

A specific variant called "papular, profuse, and precocious KP" has been identified in infants under 18 months, characterized by extensive involvement of limbs and cheeks with a distinctly papular nature 1.

Prevalence and Natural History

Keratosis pilaris is a common inherited disorder of follicular hyperkeratosis 2. While exact prevalence figures in infants aren't specified in the available evidence, it's recognized as a common skin condition in childhood that:

• Can begin in infancy (under 18 months)
• Often improves with age
• May have a genetic component with inherited mutations of the FLG gene and ABCA12 gene implicated 3
• Can be associated with other conditions like ichthyosis vulgaris 3

Variants in Infants

Several variants of KP may appear in infants:

1. KP simplex - The most common form 3
2. Papular, profuse, and precocious KP - Early onset before 18 months 1
3. Keratosis pilaris rubra - More prominent erythema, can begin as early as birth 4

Management Approaches for Infants

Treatment of KP in infants should focus on:

• Avoiding skin dryness - This is fundamental for management
• Gentle emollients - First-line therapy for infants
• Careful use of keratolytic agents - Should be used with caution in infants

Important Cautions for Infant Treatment

• Keratolytics are relatively contraindicated in the first 6-12 months due to:

  • Epidermal barrier defects
  • Immature stratum corneum
  • Higher body-surface-to-mass ratio increasing systemic absorption risk 5

• Specific precautions:

  • Salicylic acid is strictly contraindicated in children under 2 years due to risk of toxicity 5
  • Lactic acid is strictly contraindicated in children under 2 years 5
  • Urea should not be used in the neonatal period except on very limited areas such as palms and soles 5

Associated Conditions

KP in infants may be associated with:

• Ichthyosis vulgaris
• Palmar hyperlinearity
• Other genetic conditions (though less common in infants)

Clinical Pearls

• Diagnosis is often delayed in infants with KP 1
• The main complication in infants can be episodes of folliculitis 1
• Treatment can be challenging, but a combination of emollients and carefully selected keratolytic agents may provide some benefit 1
• KP is benign and often improves with age, which is important to communicate to parents

When evaluating an infant with suspected KP, it's important to distinguish it from other conditions that may present similarly, such as lichen spinulosus, phrynoderma, and trichostasis spinulosa 3.