In Table 3.1 ts tabulated the incidence of the various types of lesions in the Konpebip pecap with a breakdown as to are and the median time of appearance. Similar data are presented in Table 3.2 for the Ailinginae and Rongerik groups. 3.2.2 Description and Hlustration of Specific Lesions The scalp and forehead lesions appeared 12 to 14 days following exposure along with epiJation in the Rongelap proup. The skin lesions were maculopapular with a spotty distribution, They were concentrated in the areas of epilation. These lesions are illustrated in Plates 3.12 to 3.16. Scalp lesions continued thetr appearance over a period of about a month, Thus, groups of lesions in various stares were present in the same individual. This was particularly notable among the children, ‘The incidence of scalp lesions wag greatest In the 0 to 15 year group (see Table 3.1). The neck lesions were the most common and began theic appearance a few days after the scalp lesions. ‘Phese lesions appeared ag hyperpigmented macules and papules which spread and coalesecd into 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, Phlites 3.1 Chrough 3.4 and 3.9 iustrate neck lesiong in the various stages of development. Some of the deeper neck lesions tended to occur in women where their thick hair touched their necks. Axillary lesions were maculopapular, less abundant, and developed simultaneously 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 le- sions. hese 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 andin eight cases raw crusting lesions of varying degree followed the bullae. The foot lesions were not as common in children under 5 years of age as in the older age groups. Sequential lesions in a 14year old girl are shown on Plates 3.5 to 3.7. One of the more severe foot lesions is shown tn Plate 3.8. . - Lesions of the hands, arms, legs, and trunk were less common, less severe, and developed later. Areas of increased pigmentation were scattered over the abdomen, chest, arms, legs, and face. Increased pigmentation of the sides of the face is illustrated in Plate 3.4. A striking early lesion was an erythematous, weeping, excoriating lesion surrounding the anus which occurred tn several of the babies and a few of the older people. These lesions were severe intlinlly but healed rapidly. Most of the Marshallese iad multiple lesions. The combination of epilation and the contrasting hyperpigmented and depigmented 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 of Lesions in the VariousExposure Groups It 1s not feasible tu quantify accurately the severity and extensiveness of the skin lesions in the various yroups. However, il was the uniform opinion of all observers that the most se- vere 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 only 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. Transepidermal necrosis occurred in 20 per cent of the Rongelap and in 5 per cent of the Ailinginae people. No iesions of this severity were seen in the Rongerik group. The lesions appeared earlier in the Rongelap group suggesting a higher dose. The com- parison of the incidence of epilation and neck lesions and time of appearance is illustrated in Fig. 3.1 for the Rongelap and Ailinginae groups.