VIII. VITAMIN A DEFICIENCY IN HUMAN IJKINGS 149 



tiou of lymphoid cell.s, moiiouuclears, and leucocytes. The lining of the 

 nares, nasophaiynx, larynx, trachea, bronchi, and bronchioles is involved 

 in much the same manner but to varying degrees. 



The transitional epithelium of the renal pelvis is much more often in- 

 volved than is that of the ureter or urinary bladder. IMetaplasia occurs at 

 times in the epithelium of the uterus and prostate. In the digestive tract, 

 it has been obser\-ed chiefly in ducts of the salivary glands (where obstruc- 

 tion may cause dilation and sometimes atrophy of the acini), esophageal 

 lining, and ducts of esophageal glands. Keratinization of pancreatic ducts, 

 cystic dilation of some acini, and varying degrees of fibrosis of the pancreas 

 have been observed, but their specific relation to vitamin A deficiency is 

 questionable.^- Among other non-specific findings are atrophy of adipose 

 tissue with reversion to the embryonic glandular type, hyaline degeneration 

 of skeletal muscle fibers, arrest of bone growth and cartilage proliferation, 

 and hemosiderosis in spleen and liver. 



E. CUTANEOUS LESIONS 



The malnourished subject presenting evidence of avitaminosis A is at 

 best a variable and complex entity. Reactions of the integument, whether 

 ascribed to lack of vitamin A or not, are subject to modification by environ- 

 mental and metabolic influences which vary greatly with the age of the 

 individual. Cutaneous lesions, especially those involving the pilosebaceous 

 follicle, often present difficult problems in differential diagnosis. Further- 

 more, dermatologic terminology is not blessed with a high degree of uni- 

 formity or specificity. It is therefore not surprising that during the past 

 twenty years there has appeared an extensive but rather controversial 

 literature dealing with the character, specificity, and diagnostic value of 

 cutaneous lesions which have been observed in association with other mani- 

 festations of avitaminosis A in man. A somewhat chronologic treatment of 

 the evidence bearing on this subject provides perhaps the best means of 

 reaching a proper appreciation and evaluation of the observations recorded. 



1. Macroscopic Features in Adults 



a. Studies in China 



Although early accounts of xerophthalmia and keratomalacia contain 

 occasional reference to dry and wrinkled skin, chiefly in children, the first 

 detailed account of cutaneous changes related to avitaminosis A is con- 

 tained in the report of Pillat'^ dealing primarily with keratomalacia in 6 

 adult patients studied in the hospital of Poij)ing I^nion Medical College 

 during 1928. The hair was described as dull, dry, coarse, and brittle. The 

 skin over the entire body except that of the face was generally desiccated, 

 finely wrinkled, covered with fine scales, earthy brown to slate grey in 



