Seborrheic dermatitis affects roughly 4.4% of the global population, making it one of the most common skin conditions worldwide. A 2024 meta-analysis covering more than 1.2 million people across 121 studies found that prevalence varies significantly by age, sex, geography, and underlying health conditions.
Overall Prevalence by Age Group
The condition follows a distinctive two-peak pattern across the lifespan. The first peak hits in infancy, during the first three months of life, when about 10% of babies develop it (commonly called cradle cap). At three months specifically, prevalence spikes to around 70% before dropping steadily. By the second year of life, only about 7% of children still have it, and cases continue declining through age four. Most infant cases are mild and resolve on their own.
The second, longer-lasting peak begins after puberty and climbs through middle age, particularly after age 40. Among adults, the pooled prevalence is about 5.6%, compared to 3.7% in children and just 0.23% in newborns. This adult form tends to be chronic and recurring rather than self-limiting.
Men Are Affected More Than Women
Seborrheic dermatitis is roughly three times more common in men than in women. One large epidemiological study found it in 4.6% of males compared to 1.4% of females. The difference is thought to relate to androgens (male hormones) that increase oil production in the skin. Oil-rich areas of the face and scalp are exactly where this condition thrives, which helps explain why hormonal shifts at puberty trigger the adult form.
Prevalence Across Regions and Ethnicities
Geography matters. The global meta-analysis found the highest prevalence in South Africa at 8.8% and the lowest in India at 2.6%. Climate, genetics, and differences in how often the condition gets diagnosed all likely contribute to this range.
Among African Americans, prevalence may be slightly higher, estimated around 6.5%. In West African populations, studies place it between 2.9% and 6%. Seborrheic dermatitis also looks different on darker skin. Instead of the classic red, flaky patches, people with darker skin tones often develop scaly, lighter-colored patches. A distinct pattern called petaloid seborrheic dermatitis, featuring arc-shaped or petal-like patches, is more commonly seen in skin of color. Children of color frequently skip the typical “cradle cap” appearance and instead show flaking and lighter patches in skin folds.
For Black women in particular, scalp-related seborrheic dermatitis is among the most common reasons for visiting a dermatologist. Certain hair care practices, including heavy use of oils and pomades or infrequent shampooing, can worsen flares.
Prevalence in People With HIV or Parkinson’s Disease
In certain medical populations, seborrheic dermatitis is dramatically more common. Up to 80% of people living with HIV develop it, compared to that 4 to 6% baseline in the general population. The condition often appears earlier in the course of HIV infection and tends to be more severe and harder to manage. In fact, a sudden or unusually stubborn case of seborrheic dermatitis sometimes prompts testing for immune deficiency.
Parkinson’s disease also carries a strong association. Studies report seborrheic dermatitis in 19% to 59% of Parkinson’s patients, with one study finding it in 36% of participants. The severity of skin symptoms correlates with the severity of motor symptoms, suggesting a shared underlying mechanism involving the nervous system’s regulation of oil glands.
Seasonal Patterns
If your flares seem worse in colder months, you’re not imagining it. A large clinic-based study in Istanbul tracked seborrheic dermatitis diagnoses across all twelve months and found a clear seasonal swing. Winter and autumn together accounted for 68% of all cases, while summer accounted for just 13.5%. December was the peak month at 7.3% of all dermatology diagnoses, while June was the lowest at 3.8%.
Interestingly, autumn and winter had similar rates despite significant temperature differences between the two seasons. That suggests cold alone isn’t the driver. Lower humidity, less sun exposure, and spending more time in heated indoor air all likely play a role in winter flares.
Why the True Number May Be Higher
The 4.4% global figure almost certainly undercounts the real prevalence. Mild seborrheic dermatitis, particularly dandruff on the scalp, often goes undiagnosed because people manage it with over-the-counter shampoos and never see a doctor. The meta-analysis noted extreme variability across studies (a statistical heterogeneity score of 99.94%), meaning prevalence estimates ranged widely depending on how and where researchers looked. Studies based on clinical exams in community settings tend to find higher numbers than those relying on medical records, since many people with mild symptoms never seek care.
Some dermatologists consider dandruff to be the mildest end of the seborrheic dermatitis spectrum. If that broader definition is used, the number of people affected at some point in their lives rises substantially, with some estimates suggesting up to half of all adults experience dandruff.