Lichen striatus. This is a common and benign self-limited childhood dermatosis that is easily diagnosed from its classic appearance. Onset is usually between the ages of 3 and 10 years, and it is rare in young infants, adolescents, and adults. The lesions consist of pink, flesh-colored, or slightly hypopigmented flat-topped papules that evolve in a linear array following lines of Blaschko. The linear course of the papules may eventually traverse the major part of an extremity. The area of involvement is often noted to become wider as it advances and may even include the nails.
Granulomatous reaction caused by a bromide. Another baleful characteristic of drug eruptions from halides is persistence and extension of reaction once it occurs. The reason for such persistence or extension, even when a known source of the offending drug is removed, is the wide dispersion of occult iodine or bromine salts in foods, in the environment, and indeed in the body’s own chemistry. Iodine, for example, is a constituent of thyroid hormone.