Dermatitis: A Comprehensive Prevalence And Quality Of Life Study
Overview
The survey involved individuals aged 16 and older from 20 countries. Quota sampling was employed to reflect the population distribution by age, sex, environment, and income. Participants completed a structured questionnaire and were identified as having seborrheic scalp dermatitis (SSD) if they met the following five criteria: (1) dandruff, (2) persistent or intermittent, (3) thick, greasy, yellowish scales on the scalp, (4) associated with red patches, and (5) pruritic at times or always. The age-specific prevalence of SSD was 3.4% for those aged 16-39, 3.2% for those aged 40-64, and 2.9% for those 65 and older (p < 10−3). The prevalence varied by environment: 3.8% in urban areas, 2.1% in semi-urban areas, and 1.8% in rural areas (p < 10−3).
The overall prevalence of SSD in this study was 3.3%. Comparatively, previous studies on adult seborrheic dermatitis (aSD) reported prevalence rates between 1% and 5%. The lowest prevalence was observed in North America, while the highest was in East Asia. Consistent with aSD studies, seborrheic scalp dermatitis prevalence was highest among middle-aged adults, decreasing in the 40-64 age group and being lowest in those over 65. Unlike some aSD studies that indicated a male predominance or a slight female predominance, this study found no significant global difference in seborrheic scalp dermatitis prevalence between men and women. However, SSD was notably higher in urban areas compared to rural ones.
Introduction
Seborrheic dermatitis (SD) is a prevalent skin condition characterized by a scaly rash, typically occurring on oily regions such as the scalp and face. The appearance of the rash can vary, sometimes resembling other skin conditions. Dandruff is considered the mildest form of SD, with both conditions producing white-to-yellowish scales that can be dry or greasy and itchy. Treatments for dandruff and seborrheic dermatitis are often similar, though additional treatments may be required for seborrheic dermatitis.
Unlike dandruff, seborrheic dermatitis can manifest beyond the scalp, appearing on the ears, eyebrows, beard, and areas around the nostrils, and it may also affect the chest, particularly in men. SD causes inflammation, which distinguishes it from dandruff.
SD can develop in individuals of all ages and ethnicities, commonly starting during infancy (2 to 12 months), adolescence, or adulthood (typically in one’s 30s or later). In infants, it usually appears on the scalp and is referred to as cradle cap, though it can also occur in skin folds, on the chest, back, or in the diaper area.
SD is particularly prevalent in adults over 50, with a significant number of individuals aged 65 and older affected. In the United States, Black individuals are most prone to developing seborrheic dermatitis, and globally, men are more likely to have the condition than women. Those with HIV, neurological disorders such as Parkinson’s disease, psoriasis, or rosacea are at a higher risk of developing SD. In cases where both psoriasis and SD are present, the condition is known as sebopsoriasis. For children and adults with AIDS, seborrheic dermatitis can be widespread and challenging to treat.
In teenagers and adults, seborrheic dermatitis may resolve without intervention but can also persist for life with periodic flare-ups. These flare-ups often occur seasonally, predominantly in winter and early spring, and may subside during warm, humid weather. Stress can also trigger flare-ups. While there is no cure for SD, treatment can alleviate symptoms, reduce itching, and sometimes clear the rash.
For an accurate diagnosis, the American Academy of Dermatology advises consulting a board-certified dermatologist. This is crucial as many skin conditions cause itchy rashes, and seborrheic dermatitis can co-exist with other conditions like rosacea or psoriasis. Early treatment is recommended to prevent the thickening of scales and potential infections from scratching. In individuals with darker skin tones, seborrheic dermatitis can cause noticeable dark spots and patches, especially on the face, which early treatment can help prevent.
A study was conducted to assess the prevalence, demographics, healthcare trends, and impact on the quality of life of individuals with scalp seborrheic dermatitis (SSD). This international survey included participants aged 16 and older from 20 countries, using quota sampling based on age, sex, environment, and income distribution. Participants who reported all five of the following criteria were considered to have SSD: persistent or intermittent dandruff, thick greasy yellow scales on the scalp, associated red patches, and pruritus.
By addressing these findings, the study aims to enhance understanding and management of SD, providing tailored treatments and improving patient outcomes.
Result
The study revealed that the prevalence of seborrheic dermatitis (SSD) varied with age and location. It was highest at 3.4% among individuals aged 16 to 39, followed by 3.2% for those aged 40 to 64, and lowest at 2.9% for those aged 65 and older (p < 0.001). Geographically, urban areas had the highest prevalence at 3.8%, compared to 2.1% in semi-urban and 1.8% in rural areas (p < 0.001). Overall, SSD prevalence was 3.3%, consistent with previous studies on seborrheic dermatitis (aSD), which reported a prevalence between 1% and 5%, with the lowest rates in North America and the highest in East Asia.
In contrast to some aSD studies that indicated a male predominance or a slight female predominance, this study found no significant difference in SSD prevalence between men and women globally. However, seborrheic scalp dermatitis was notably higher in urban settings, likely due to higher pollution levels increasing Malassezia spp. populations.
North America had the lowest rate of individuals seeking medical attention for seborrheic scalp dermatitis. Furthermore, the proportion of those visiting a dermatologist was also lower in North America, potentially due to higher healthcare costs in the U.S. and Canada. While both genders reported similar levels of personal embarrassment, men experienced significantly more professional embarrassment, possibly due to more visible symptoms from shorter hair or hair loss and women’s ability to conceal scalp disorders through styling.
SSD had a significant impact on younger individuals (16–40 years old) and men, affecting their work or studies, leisure activities, and self-perception. This group was more likely to skip work, vacations, and beauty treatments, frequently check their appearance, and feel avoided or looked at with disgust by others. This contrasts with smaller aSD studies that reported a higher quality of life impact on females.
Limitations of this study include potential selection bias due to low internet usage in countries like Senegal, South Africa, and India.
Conclusion
In summary, this pioneering global study on SSD revealed that North America had one of the lowest prevalence rates of SSD and the fewest SSD patients seeking dermatological care, whereas East Asia reported the highest prevalence. The study found no significant gender differences in prevalence; however, men experienced a greater impact on quality of life (QoL). This underscores the importance for healthcare providers to evaluate QoL in SSD patients, particularly men, to ensure they receive comprehensive medical and psychological support. Future research should focus on identifying clinical factors that predict SSD-related QoL alterations to further enhance patient care.
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