Seborrheic dermatitis and the closely related condition "dandruff" are two scaly scalp conditions that are common in the general population. I'm often asked if these conditions can cause hair loss. It is a fact (not a speculation) that seborrheic dermatitis can cause an individual to experience increased hair shedding (telogen effluvium). This has been shown many times in various studies.
Dr Pierard- Franchimont and colleagues have done very interesting research in the area of seborrheic dermatitis and dandruff. They showed about 10 years ago that the more seborrheic dermaitits a person has, the more shedding (telogen effluvium) a person will experience. This is important information to know because it tells us that individuals with severe seborrheic dermatitis are likely to have a severe telogen effluvium. Dr Pierard Franchimont and others have also shown data that the inflammatory reaction can even accelerate male balding in some cases making it important to aggressively treat seborrheic dermatitis in patients with hair loss.
There is no doubt about the relationship between seborrheic dermatitis and shedding. Companies that manufacture dandruff shampoos study shedding patterns to determine if their shampoo is working. Anti-dandruff shampoos can reduce shedding.
In summary, seborrheic dermatitis can certainly cause a telogen effluvium. This photo shows the scalp of a patient with moderate seborrheic dermatitis. Numerous upright regrowing hairs (URH) are seen, which is a typical sign of a hair cycling abnormality (telogen effluvium).
Dandruff-associated smouldering alopecia: a chronobiological assessment over 5 years.
Piérard-Franchimont C, et al. Clin Exp Dermatol. 2006.
Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Vancouver office at 604.283.9299