Low Prevalence of Keratosis Pilaris in Patients with Atopic Dermatitis

Keratosis pilaris has often been associated with AD and filaggrin loss-of-function mutations, the latter of which are frequent in Europe with an approximate prevalence of 7%

A new cohort study from Finland determined that the prevalence of keratosis pilaris (KP) was relatively low in patients with atopic dermatitis (AD).

Keratosis pilaris has often been associated with AD and filaggrin (FLG) loss-of-function mutations, the latter of which are frequent in Europe with an approximate prevalence of 7% and are responsible for an increased risk for atopic diseases.

Previous research has shown that KP associated with epidermal barrier defects in AD, yet its role in disease severity prediction and concomitant atopic diseases is uncertain.

Because of this, an investigative team led by Alexander Salava, MD, PhD, of Helsinki University Hospital, explored the occurrence of KP in Finnish patients with AD as well as the link to frequent FLG loss-of-function mutations.

The team performed a cross-sectional study with 502 randomly selected AD patients from a Finnish tertiary health care center, with patient recruitment being carried out between 2011-2015.

Each eligible patient with AD were examined based on disease severity and history. Data on disease onset, hereditary factors related to first-degree relatives, contact allergy, prick positivity, peanut allergy, and atopic comorbidities were also collected.

Investigators also investigated total serum IgE-levels and FLG null-mutations of each patient during clinical visits, and all laboratory tests were carried out at the Laboratory of Helsinki University Hospital.

A total of 347 patients were enrolled in the cohort, only 28 of whom had KP. Despite this low number of patients with the skin condition, investigators observed that KP was not associated with AD severity based on EASI at the clinical visit (P=0.3232) (95% CI 0.276–0.357) and RLS (P= 0.649) (95% CI 0.569–0.654).

Additionally, no significant links to total serum IgE levels, early AD onset or positive history of hand dermatitis, contact allergy, asthma, or prick positivity were seen.

Notably, KP was significantly associated with the FLG LoF mutation 2282del4 (P < 0.000) (95% CI 0.000–0.009, OR 4.917, 95% CI 1.961–12.330), but not with any other sequenced mutations featured in the study.

Overall, KP in Finnish patients with AD seemed to be infrequent, which investigators believed could have been due to the fact that the tested FLG loss-of-function mutations were overall rarer in Finnish populations when compared to others in central Europe or Asia.

“Mutations in other locations of the FLG gene or other genes of the epidermal barrier may play a more important role in Finnish patients and need further research,” the team wrote.

The study, "Keratosis pilaris and filaggrin loss-of-function mutations in patients with atopic dermatitis – Results of a Finnish cross-sectional study," was published online in the Journal of Dermatology.