SKIN LESIONS AND EPILATION Biopsies of three pigmented lesions were taken from 2 of the white Americans of the Rongerik group. Only 1 of 3 showed evidence of damage, which was slight and confined to the epidermis. Third series—6th month post-exposure. Sections of skin at this time revealed some changes persisting in the epidermis and to a lesser extent in the dermis (Plates 28 and 29). Epidermis. The following changes were foundto varying degrees: focal atrophy of the stratum granulosum; slight focal pigmentary disturbancesin cells of the basal layer; slight to moderate hyperkeratinization; and slight disturbances in polarity of epithelial cells in the still persistent basal papillary projections. Dermis. In the dermis, telangiectasis super- ficially persisted from a slight to moderate degree in mostof the sections, and contributed the only abnormality noted. 3.33 Epilation and Nail Pigmentation Epilation. The incidence and time of appearance of epilation in the various groupsis illustrated in Tables 3.1 and 3.2, and Figure 3.1. Epilation was first observed of the fourteenth post-exposure day in the Rongelap group, and somewhat later in the other groups. It was of aspotty nature and was confined almost entirely to the head region. Epilation was divided arbitrarily into 3 degrees of severity. “1+” indicated loss of hair without obvious thinning; “2+indicated loss of hair sufficient to cause thin spots; and “3+” indicated an extensive epilation with bald spots. Table 1 illustrates that there was a greater degree of epilation in the children (0 to 15 years), with over 90 percent developing epilation to some degree as compared to only 28 percent in the older age group. The preponderance of scalp lesions in the areas of epilation indicated that radiation from the fallout material on the skin was primarily responsible for the epilation. Only three eases of mild epilation developed in the Ailinginae children, and questionable epilation 33 occurred in one of the Americans, characterized by loose hair upon combing but without areas of alopecia. Regrowth of hair in all individuals commenced some time during the third monthafter exposure. At the 6 months’ examination complete regrowth of hair, normal in color, texture, and abundance had taken place. Plates 13-15, 17, 18, and 19 showepilation and regrowth of hair. Nail Pigmentation. An unusual observation was the appearanceof a bluish-brownpigmentation of the fingernails which wasfirst well documented onthe 28rd post-exposure day. Thediscoloration began in the semilunar area of the fingernails (to a lesser extent in the toenails), and spread outward sometimes in streaks. .As the discolored area grewdistally the semilunar area usually became clear. Plate 20 showspig- mented bandsin the nails at 77 days. At six months, pigmentation had grown out with the nails, and was no longer evident except in three cases which still showed pigment at the distal end of thenail. The pigment was on the underside of the nail plate. Discoloration of the nails was seen in a large proportion of the two higher exposure groups (Tables 3.1 and 3.2). The phenomenonappeared to be a radiation response peculiar to the dark-skinned races since it was seen in all of the exposed American Negroes and none of the white Americans supposedly receiving the same exposure. This lesion was not observed in the Utirik people or in unexposed Marshallese. Since the nail pigmentation occurred in individuals without skin lesions, it appeared to be the result of a more penetrating gamma component of radiation. 3.4 Therapy Tue Treatment Or the skin lesions was largely non-specific. Most of the superficial lesions were treated with calaminelotion with one percent phenol, which in most cases relieved the itching and burning. A few of the hyperpigmented lesions not relieved by calamine with phenol were treated with pontocaine