Mast cell disease (MCD) includes children and adults with mastocytosis and mast cell activation syndrome (MCAS). Mastocytosis is most common in children, and results from activating mutations in KIT, leading to uncontrolled MC proliferation. Increased MCs are often found in the skin (cutaneous mastocytosis; CM), but also may occur in the bone marrow and other organs (systemic mastocytosis, SM). Childhood disease usually involves only the skin, and frequently resolves by adolescence. Adult-onset mastocytosis persists throughout life, and has variable cutaneous and systemic involvement. Subsets of SM include: indolent SM (ISM), smoldering SM (SSM), aggressive SM (ASM), SM with an associated hematologic neoplasm (SM-AHN) and mast cell leukemia (MCL). Cutaneous mastocytosis and ISM are most common in adults. Patients with MCAS have many of the symptoms of mastocytosis but lack persistent skin lesions and have no evidence of uncontrolled mast cell proliferation.
Treatment of MCD is directed at alleviating symptoms, and in more severe cases reducing MC burden, since there is no cure. Many patients with CM and ISM have few, if any, symptoms, and therefore require little or no therapy. Avoiding potential MC stimuli is recommended. For patients with symptoms of histamine release, second-generation, H1 antihistamines are preferred due to their longer half-lives and greater specificity for H1 receptors. I have found fexofenadine up to 360 mg in the morning and cetirizine (10-40 mg) at night effective for these patients. For those who are poorly responsive to antihistamines, light therapy (psoralen + UVA, PUVA or narrowband UVB, NBUVB), and omalizumab have proven useful. Treatment of advanced SM (ASM, SM-AHN, and MCL) often requires aggressive systemic therapy that is best implemented in collaboration with a hematologist or an oncologist. See Table 28-1.
Table 28-1Mastocytosis Treatment Table ||Download (.pdf) Table 28-1 Mastocytosis Treatment Table
|TREATMENT ||INDICATION ||MECHANISM OF ACTION ||DOSING ||ADVERSE EFFECTS ||RECOMMENDED MONITORING ||LEVEL OF EVIDENCE (REFERENCE) |
|Avoidance of Potential MC Stimuli |
|Physical; friction, exercise, heat, cold ||CM/SM ||Direct MC stimulation ||NA ||Flushing, itching, GI sxs, hypotension ||NA ||IV1 |
|Dietary; alcohol, hot beverages ||CM/SM ||Direct MC stimulation ||NA ||Flushing, itching, GI sxs, hypotension ||NA ||IV1 |
|Medications; ASA, NSAIDs, opiates (eg, morphine, codeine), dextromethorphan (a cough suppressant), polymyxin B sulfate, some systemic anesthetics, including lidocaine, d-tubocurarine, metocurine, etomidate, thiopental, succinylcholine hydrochloride (suxamethonium chloride), enflurane, isoflurane, iodine-based radiographic dyes dextran (in some IV solutions) ||CM/SM ||Direct MC stimulation ||NA ||Flushing, itching, GI sxs, hypotension ||NA ||IV1-3 |
|Topical Therapy |
|Potent topical corticosteroids ||CMa ||Inhibit MC mediator release & MC growth ||QD under occlusion × 12 wk ||Skin atrophy ||q2-3mo ||IIB4 |
|Topical calcineurin inhibitors ||CMa ||Inhibit MC mediator release & MC growth ||Bid to lesions × mo ||Stinging with initial applications ||None ||III5 |
|Intralesional corticosteroids ||CMa ||Inhibit MC mediator release and MC growth ||5-20 mg/mL ||Skin atrophy ||With repeated injections ||III4...|