Many cases of cutaneous mastocytosis remain confined to the skin, but some may indicate a risk for systemic mastocytosis (SM), which affects multiple organs, according to a study of two pediatric patients published recently in The American Journal of the Medical Sciences.
Cutaneous mastocytosis is a rare condition in which excessive mast cells accumulate in the skin and can cause persistent rashes, itching and allergic reactions in children.
What is SM?
Systemic mastocytosis (SM) is a rare hematological disease characterized by mast cells that are overactive and accumulate in different parts of the body such as the bone marrow, liver, spleen, gastrointestinal tract and lymph nodes.
Early diagnosis, symptom management with antihistamines and close monitoring for systemic progression are essential for improving patient outcomes.
Read more about SM testing and diagnosis
“Rashes are commonly benign in the pediatric population, but cutaneous mastocytosis should be on the differential when associated with itching, flushing and abdominal pain,” study authors said. “Cutaneous mastocytosis is rare in the pediatric population, but if not controlled can lead to an increased risk of allergic reactions including anaphylaxis.”
The two recent cases highlighted the importance of recognizing the disorder in young children.
While most pediatric rashes are harmless, cutaneous mastocytosis should be considered in children with persistent itching, flushing or unexplained allergic reactions, study authors said. Early diagnosis and appropriate management can help prevent complications, improve quality of life and ensure that any potential systemic progression is detected promptly.
A 19-month-old boy with iron deficiency anemia and thrombocytosis was referred to a hematologist for persistent anemia. A routine blood test revealed an elevated eosinophil count, and a physical examination identified a small chest lesion that became red, swollen and itchy when rubbed.
A skin biopsy confirmed cutaneous mastocytosis, showing excessive mast cell proliferation in the dermis. He experienced occasional outbreaks of hives, which responded well to cetirizine, an antihistamine. While his anemia, eosinophilia and thrombocytosis were likely linked to his condition, further testing ruled out systemic involvement.
The second case involved a 2-month-old boy born prematurely at 32 weeks, who developed brown lesions on his trunk and extremities within months of birth. A dermatology evaluation led to a skin biopsy that confirmed cutaneous mastocytosis, with immunostaining positive for CD117 and tryptase, markers for mast cells.
Although his initial symptoms were mild, he later developed enlarged lymph nodes, an enlarged spleen and rising levels of tryptase, raising concerns about SM. Despite these findings, a bone marrow test confirmed no systemic involvement, and he began treatment with cetirizine to manage symptoms.
Cutaneous mastocytosis primarily affects the skin, with the trunk and extremities being the most common sites. Symptoms include rashes, itching, and flushing, often triggered by heat, stress or certain medications. Antihistamines help control symptoms, and avoiding triggers is key to preventing flare-ups. In rare cases, children with this condition may experience severe allergic reactions, including anaphylaxis.
SM, a more serious form of the disease, can involve the liver, spleen and lymph nodes. Blood tests measuring serum tryptase levels and genetic testing for c-KIT mutations can help determine if systemic involvement is present. A bone marrow biopsy is necessary if recurrent systemic symptoms or organ involvement are suspected.
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