There are several types of keratosis pilaris (KP), including rubra faceii, the form affecting this patient (distinguished in part by involvement of the facial skin). KP is utterly common, affecting 30% to 50% of the white population worldwide, with no gender preference. This autosomal dominant disorder involves follicular keratinization—normal keratin (produced in the hair follicle) builds up and creates a “plug” that manifests as a firm, dry papule. Obstruction of the follicular orifice may be significant enough to prevent hair from exiting, in which case, the hair continues to grow but simply curls in on itself and accentuates the appearance of the papule.
Although KP is a condition and not a disease, it is often considered part of the atopic diatheses, which include the major diagnostic criteria of eczema, urticaria, and seasonal allergies. KP is often mistaken for acne, especially when it affects the face, but its lack of comedones and pustules is a distinguishing characteristic.
Keratosis follicularis (Darier disease) also features follicular papules, but the distribution and morphology differ significantly. Darier is a more serious problem in terms of extent and symptomatology.
Treatment of KP is unsatisfactory at best, but emollients can make it less bumpy. Salicylic acid and lactic acid–containing preparations can also help, but only temporarily. Gentle exfoliation followed by the application of heavy oils is considered the most effective treatment method. The most encouraging thing we can tell our patients: The problem tends to lessen with age.
TAKE-HOME LEARNING POINTS
- Keratosis pilaris (KP) is a common inherited defect of follicular keratinization that affects 30% to 50% of the white population worldwide.
- KP results in a distribution of follicular rough papules across the face, triceps, thighs, buttocks, and upper back, beginning in early childhood.
- A significant percentage of affected patients exhibit the variant termed rubra faceii, which involves the posterior 2/3 of the bilateral face.
- Treatment is problematic, but the application of emollients after gentle exfoliation can help; most cases improve as the patient ages.