It is well known that zinc exerts important activities affecting skin, hair follicle, keratinocyte and melanocyte health and function. However, there have been mixed results with finding a link between low zinc level and alopecia areata (AA) incidence. Therefore, a recent randomised case-control study examined whether low zinc levels were evident in new and resistant cases of AA, with positive results.[1,2]
Using the results of the severity of alopecia tool (SALT), subgroups were formed from the 50 sufferers of AA and 50 sex- matched healthy control trial participants. In those with AA, 25 had been diagnosed within one to three months, the other 25 had a resistant form with disease duration from 6-30 months. Fasting blood was taken from each subject and plasma zinc levels recorded.
The researchers found lower serum zinc levels were statistically highly significant in the AA patients compared to the controls, with a significant decrease in levels within the AA resistant group compared to the newly diagnosed group. Additionally, the zinc level affected the extent and duration of AA. This meant the lower the zinc level the greater the impact on AA.
AA is thought of as an autoimmune and inflammatory condition, with infiltration into the hair follicles of cytotoxic T cells. Defects in T cell function is typical in zinc deficiency.[1,2]
The skin has the third highest abundance of zinc in the body and this mineral plays many physiological roles in wound healing, cell survival and reduction in inflammation. When there is a zinc deficiency, KC proliferation, differentiation and survival are reduced. Increases in inflammatory cytokines and inducible nitric oxide synthase (iNOS) and nitric oxide synthase (NOS) are also seen, which can increase free radical activity. Additionally, zinc deficiency may affect hair phase growth and abnormal hair keratinisation, causing weakened hair shafts, hair breakage and slow hair regrowth.[1,2]
Zinc in adequate amounts also inhibits tyrosinase, the rate-limiting enzyme of hair follicle melanin production. It is also an essential component of the antioxidant complex, copper/zinc superoxide dismutase, suggesting that zinc-copper ratios may be important in patients with AA.[1,2]
This study is the first in assessing the relationship between zinc and newly diagnosed and resistant AA and may suggest serum zinc levels as a potential marker for AA severity with a possible role in resistance of AA to treatment.[1,2]
- Ogawa Y, Kawamura T, Shimada S. Zinc and skin biology. Arch Biochem Biophys 2016. [Abstract]
- Abdel Fattah NS, Atef MM, Al-Qaradaghi SM. Evaluation of serum zinc level in patients with newly diagnosed and resistant alopecia areata. Int J Dermatol 2016;55(1):24-29. [Abstract]