In Table 3.1 is tabulated the incidence of the various types of lestons in the Ronpelap paoup with a breakdown as to age and the median time of appearance. Similar data are presented in Table 3.2 for the Ailinginmae and Rongerik groups. 3.2.2) Description and Hlustration of Specific Lesions The scalp and forehead lesions appeared 12 to 14 days following exposurealong with epiJation in the Rongelap group. The skin lesions were maculopapular with a spotty distribution. They were concentrated inthe areas of epilation. These lesions are illustrated in Philes 3.12 to 3.16. Scalp lesions continued their appearance over a period of about a month. Thus, groups Mf lesions in various stages were present in the same individual. This was particularly notable among the children, ‘Phe incidence of scalp lesions was greatest in the 0 to 15 year proup (see Table 3.1). The neck lesions were the most common and began their appearance a few days after the scalp lesions. These lesions appeared as hyperpizmented macules and papules which spread and combescod dato raised plaques. The lesions usually appeared first on the side and front of the neck and spread backwards. They were more common and more severe in women, Plates 3.1 through 3.4 and 3.9 illustrate neck lesions in the various stages of development. Some of the deeper neck lesions tended to oecur in women where their Chick hair touched thetr necks. Axillary lesions were maculopapular, less abundant, and developed simultanevusly with the neck lesions. These lesions are illustrated in Plates 3.10 and 3.11. The axillary lesions were more common in the young children. Antecubital fossae lesions appeared about a week later than did the neck and axillary leSions. These are illustrated in Plates 3.9 and 3.10. The foot lesions developed later than the lesions of the antecubital fossae. These lesions were located mainly on the dorsum of the foot between or on the toes. They wereinitially characterized by large pigmented plaques with subsequent bullous formation and in eight cases raw crusting lesions of varying degree followed the bullae. The foot lesions were not as com- mon in children under 5 years of age as in the older age groups. Sequential lesions ina 14- year old girl are shown on Plates 3.5 to 3.7. One of the more severe foot lesions is shown in Plate 3.8. - . Lesions of the hands, arms, legs, and trunk were less common, less severe, and developed later. Areas of invreased pigmentation were scattered over the abdomen, chest, arms, legs, and face. Increased pigmentation of the sides of the face is iliustrated in Plate 3.4. A striking early lesion was un erythematous, weeping, excoriating lesion surrounding the anus which occurred in several of the babies and a few of the older people. These lesions were severe initially but healed rapidly. Most of the Marshallese had multiple lesions. The combination of epilation and the contrasting hyperpigmented and depipmented areas adjacent to normal skin presented a striking appearance. The multiple lesions are illustrated in Plates 3.8 to 3.11. 3.2.3 Severity and Time Appearance ofLesions in the Various Exposure Groups it is not feasible tu quantify accurately the severity and extensiveness of the skin lesions in the various groups. However, it was the uniform opinion of all observers that the most severe and extensive lesions occurred in the Rongelap group. The lesions that developed in the Ailinginae group were much less severe and extensive, and the Rongerik group (Americans) had onty mild lesions. Skin lesions were completely absent in 60 per cent of the Rongerik group, as opposed to approximately 10 per cent in both the Rongelap and Ailinginae groups. 1’ . aeete + Transepidermal necrosis. occurred in 20 per cent of the Rongelap and in 5 per cent of the Ailinginae people. No lesions of this severity were seen in the Rongerik group. The lesions appeared earlier in the Rongelap group suggesting a higher dose. The comparison of the incidence of epilation and neck lesions and time of appearance is illustrated in Fig. 3.1 for the Rongelap and Ailinginae groups.