Investigators believe that the prevalence of rosacea familiarity had been underestimated in previous reports.
A recent investigation into rosacea intrafamilial transmission found that the prevalence of familial rosacea was nearly 70%, and that nearly half of all participants were positive for at least 1 family member with the skin condition.
In previous research, rosacea hereditary predisposition had been hypothesized based on family inheritance and twin concordance.
Though the physiopathology of rosacea is unclear and multifactorial, several factors such as genetic susceptibility, positive family history, immune/neurovascular dysregulation, vascular and neuronal dysfunction, and local proliferation of skin commensals have been considered.
As such, a team of investigators led by Giuseppe Micali, MD, Dermatology Clinic at the University of Catania, Italy, assessed data on rosacea intrafamilial transmission across 6 generations.
From June 2018 to June 2019, investigators enrolled patients with rosacea from the acne and rosacea clinic of the University of Catania.
A total of 130 adult patients were enrolled, 93 of whom were female. The mean age of participants was 49 years.
Demographic and lifestyle characteristics, anamnestic and clinical data, and severity grade were collected from each participant before queries on familiarity and interfamilial transmission up to 6 generations were performed.
Several modalities were considered including horizontal transmission that encompasses all family members who do not directly descend from the proband, vertical transmission that included all family members who directly descend from the proband in an ascending and/or descending trend, and combined transmission of both horizontal and vertical transmission.
Regarding prominent phenotypes, investigators noted that fixed centrofacial erythema +/-telangiectasias+ papules/pustules lesions were present in 67 (51.5%) patients.
This was followed by fixed centrofacial erythema+/- telangiectasias in 49 (37.8%), phymatous changes in 5 (6.9%) or ocular manifestations in 9 (3.8%).
Overall rosacea severity was mild in 45 (34.6%) patients, moderate in 70 (53.8%) and severe in 15 (11.6%), and a statistically significant association was found between fixed centrofacial erythema +/- telangiectasias + papules and pustules phenotype and female gender (p=0.0001).
Additionally, statistically significant associations were observed with phymatous changes with male sex (p=0.0001), normal weight (p=0.009), and smoking (p=0.026); ocular symptoms with alcohol consumption (p=0.01).
In terms of familiarity, 64 out of 130 patients (49.2%) were positive for at least 1 family member.
Among them, 28 (43.8%) were affected by fixed centrofacial erythema+/- telangiectasias, while 26 (40.6%) were affected by fixed centrofacial erythema +/- telangiectasias + papules/pustules, and (14%) and 1 (1.6%) by ocular manifestations or phymatous changes, respectively.
Following an accurate familial anamnestic investigation of the whole kindred, 90 affected relatives of the probrand group (69.2%) were identified.
Among them, 45 (50%) showed fixed centrofacial erythema +/- telangiectasias, 32 (35.5%) fixed centrofacial erythema +/- telangiectasias + papules/pustules, and 10 (11%) and 3 (3.5%) ocular manifestations or phymatous changes respectively, with severity rates being mild in 39 (43.4%), moderate in 42 (46.6%) and severe in 9 (10%).
Reharding rosacea inheritance, vertical transmission was recorded in 45 (70.3%) probands, horizontal in 11 (17.2%) and combined in 8 (12.5%).
Based on the data, investigators believed that the prevalence of rosacea familiarity had been underestimated in previous reports, adding that a more accurate investigation was advisable.
“Extending the search to all potential affected parents or offspring of rosacea patients with a positive family history can promote early diagnosis aimed at the adoption of correct therapeutic intervention and educational programs to prevent the exposure to triggering or exacerbating factors,” the team wrote. “Further Genome Wide Associations (GWAS) studies are however needed to better investigate specific genetic factors associated to familial rosacea risk, and to identify links between the gene variants and the expressed rosacea phenotype.”
The study, "Intrafamilial Transmission of Rosacea Spanning Six Generations: A Retrospective Observational Study," was published online in the Journal of Clinical and Aesthetic Dermatology.