96
Mastocytosis
• Spectrum of disorders caused by proliferation and accumulation of mast cells in the skin and/or other tissues (Table 96.1).
Table 96.1
WHO classification of mastocytosis.
Patients with disorders in the bottom two rows usually do not have cutaneous lesions.
• Childhood-onset mastocytosis generally has a benign course with spontaneous remission prior to puberty, whereas adult-onset mastocytosis typically persists and may be associated with systemic involvement (Fig. 96.1).
Clinical Features of Cutaneous Mastocytosis
• Firmly rubbing or stroking cutaneous lesions of mastocytosis often causes urtication (Darier’s sign) (Fig. 96.2); this is generally more pronounced in children.
Fig. 96.2 Darier’s sign in mastocytosis. An infant with extensive cutaneous involvement (A) and an adult with macular and papular lesions (B). A, Courtesy, Julie V. Schaffer, MD; B, Courtesy, Thomas Horn, MD.
• In approximately half of patients, hiving develops after stroking clinically uninvolved skin (dermatographism).
Mastocytomas (Solitary or Multiple)
• Typically present at birth or appear during infancy.
• One to several papules, nodules, or plaques with a yellow-tan to red-brown color and leathery (peau d’orange) texture (Fig. 96.3).
Fig. 96.3 Mastocytoma in an infant. Note the leathery appearance of the skin and the two erosions. Courtesy, Michael Tharp, MD.
• Can occur anywhere on the skin surface, including acral sites.
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