<unk>  in the form of XP can be diagnosed from clinical impression, although in some cases it may need to be distinguished (differential diagnosis) from other conditions, especially necrobiotic xanthogranuloma, syringoma, palpebral sarcoidosis, sebaceous hyperplasia, Erdheim–Chester disease, lipoid proteinosis (Urbach–Wiethe disease), and the syndrome of adult-onset asthma and periocular xanthogranuloma (AAPOX). Differential diagnosis can be accomplished by surgical excision followed by microscopic examination by a pathologist (biopsy to determine histopathology). The typical clinical impression of XP is soft, yellowish papules, plaques, or nodules, symmetrically distributed on the medial side of the upper eyelids; sometimes the lower eyelids are affected as well.
Xanthelasma
Onychophosis
Melasma
Hypertrichosis cubiti
Woolly hair nevus
Koilonychia
Onychogryphosis
Halo nevus