PracticeUpdate Dermatology February 2019

EXPERT OPINION 23

Check for lymphadenopathy and hepatosplenomegaly. If there is a suspected abnormality, a liver ultrasound or CT scan is indi- cated. A complete blood count (CBC), serum tryptase level, LFTs, and kit gene analysis can be obtained (although it is considered by some to be optional in the pediatric population). Bone marrow involvement is not very common in children with cutaneous mas- tocytosis, as opposed to adults, and a bone marrow biopsy is not usually recommended. Treatment revolves around avoiding triggers that cause mast cell degranulation (see reference for a detailed list of drugs and anes- thetics) and treating symptomatic patients (antihistamines; oral cromolyn sodium for GI symptoms). 4 Although topical steroids and phototherapy (PUVA, narrow band UVB, UVA1) have been utilized, if patients are asymptomatic, given the overall good prognosis, I usually do not treat the skin at all (especially in this age of ster- oid phobia). I might change my approach. Since 2005 when Lee et al reported the case of an 86-year-old man with telangiectasia macularis erup- tive perstans that responded to topical pimecrolimus, 5 there have been just a smattering of reports utilizing calcineurin inhibitors (more for pimecrolimus than tacrolimus) for mastocytosis. Ma et al demonstrated that pimecrolimus decreases the density of murine cutaneous mast cells and subsequent reduction of histamine pro- duction by inducing mast cell apoptosis. 6 Mashiah et al performed a retrospective study in which 18 children with cutaneous mastocy- tosis (mastocytomas and urticaria pigmentosa) treated with topical pimecrolimus 1% (11 male, 7 female; age range, 3–42 months) were evaluated. 7 Of the 146 treated lesions, 39 (26.7%) disappeared and 98 (67%) faded or developed post-inflammatory hyperpigmentation.

Of the 119 papular lesions, 24 (16.4%) showed partial flattening and 56 (47%) became macular. Darier sign became negative in 14 of 17 patients (82%). No topical or systemic complications were observed. Although this was not a randomized, prospective, controlled study, I will undoubtedly prescribe pimecrolimus in my next cutaneous mastocytosis encounter. Point to Remember: Pediatric cutaneous mastocytosis regresses in most, but not all, cases. Topical calcineurin inhibitors, notably pimecrolimus, may have therapeutic value. Disclaimer: First published on Dr. Warren Heymann’s Dermatology Insights and Inquiries website on September 3, 2018. Republished with permission. References 1. Macri A, Cook C. Urticaria Pigmentosa (Cutaneous Mastocytosis) [Updated 2018 Oct 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2018 Jan. 2. Méni C, Bruneau J, Georgin-Lavialle S, et al. Paediatric mastocytosis: a systematic review of 1747 cases. Br J Dermatol 2015;172(3):642-651. 3. Klaiber N, Kumar S, Irani AM. Mastocytosis in children. Curr Allergy Asthma Rep 2017;17(11):80. 4. Hermans MAW, Arends NJT, Gerth van Wijk R, et al. Management around invasive procedures in mastocytosis: an update. Ann Allergy Asthma Immunol 2017;119(4):304-309. 5. Lee HW, Jeong YI, Choi JC, et al. Two cases of telangiectasia macularis eruptive perstans demonstrated by immunohistochemistry for c-kit (CD 117). J Dermatol 2005;32(10):817-820. 6. Ma Z, Tovar JP, Kwong KY, Paek D. Pimecrolimus induces apoptosis of mast cells in a murine model of cutaneous mastocytosis. Int Arch Allergy Immunol 2010;153(4):413-418. 7. Mashiah J, Harel A, Bodemer C, et al. Topical pimecrolimus for paediatric cutaneous mastocytosis. Clin Exp Dermatol 2018;43(5):559-565. www.practiceupdate.com/c/78933

VOL. 3 • NO. 1 • 2019