What is immunity and What causes dry skin?

Immune System

The immune system helps to monitor and fight infection and prevent  cancer.  It  includes  specialized  white  blood  cells—T cells,  B  cells, and  neutrophils—that  are  always  on  call  to  help. Your  body’s  immune  system  is  like  an  army  with  millions  of soldiers,  ready  to  fight  foreign  substances  such  as  germs  and viruses in the body. As we age, certain  parts  of  the  system  diminish  in  vitality, and we  have  to  be  more  alert  to  help  boost  the  system  to  work  at full  capacity.  In  autoimmune  diseases,  such  as  lupus,  the  immune system is out of control and attacks healthy tissues.

Dry Skin

Xerosis  (dry  skin)  is  a  common dermatological  skin  condition. Dry skin, or  xeroticeczema, can  be  labeled  as  xerosis, eczema craquele  (like  a  pattern  of  cracked  porcelain),  or  asteatotic eczema  (Plate2).  The  incidence  increases  with  age  and  is common in older individuals. The reduced  production  of  sebum  also  may  play  a  role  in  dry skin. Sebum contains  wax esters, triglycerides, and  squalene, all of  which protect  the  skin  from  the  environment. Certain  individuals  receiving  cholesterol-reducing  drugs  exhibit  dry  skin. Natural  moisturizing  factor,  a  substance  that  retains  water inside  keratinocytes  and  renders  them  plump,  also  plays  an important role in the pathophysiology of dry skin. Defects  in  the  stratumcorneum or barrier can result  in  transepidermal  water  loss,  which  dehydrates  the  skin  and  imparts a  dry  appearance.  An  impaired  barrier  may  also  make  skin more  susceptible  to  damage  from  exogenous  sources  such  as plants,  chemicals,  and even water.