Practice Points
1. Guttate psoriasis, which may follow a throat infection in predisposed people, displays a relatively uniform eruption of scaly spots.
2. Pityriasis rosea is characterized by a preceding 'herald patch'; larger lesions over the trunk, proximal limbs and throat; peripheral collarettes of scale; and a 'fir tree' distribution over the trunk.
3. Secondary syphilitic eruptions are generally monomorphous and typically involve the palms, soles, oral/genital mucosa, scalp and face. However syphilis may mimic a wide variety of skin conditions, so the possibility must always be kept in mind.
4. Varicella appears first over the face and scalp, spreading to the trunk but with relative sparing of the extremeties, and is accompanied by systemic symptoms. It features a polymorphous eruption of lesions in all stages of developement, ranging from macules to papules, superficial thin-walled vesicles, pustules, crusts and post inflammatory marks.