Overview
Bullous diffuse cutaneous mastocytosis (BDCM) is a rare and severe form of mastocytosis that primarily affects infants and young children. In this condition, mast cells — a type of immune cell normally found in small numbers in the skin — build up in large amounts throughout the skin. This leads to widespread skin involvement with blistering (bullae), thickened skin, and intense itching. The blisters can be large and may break open, leaving raw, painful areas that are at risk for infection. Mast cells contain chemicals like histamine that, when released in excess, can cause flushing, low blood pressure, rapid heartbeat, abdominal pain, and diarrhea. In severe cases, massive release of these chemicals (called anaphylaxis) can be life-threatening. The skin may appear yellowish-brown or reddish and may swell when rubbed or irritated, a reaction known as the Darier sign. Treatment focuses on controlling symptoms and preventing mast cell activation. Antihistamines are the cornerstone of therapy, and medications like cromolyn sodium may help with gastrointestinal symptoms. Avoiding known triggers — such as extreme temperatures, friction, certain medications, and insect stings — is essential. In many children, the condition improves significantly by adolescence, though careful monitoring is needed throughout childhood. Emergency treatment with epinephrine may be required if severe allergic-type reactions occur.
Also known as:
Key symptoms:
Widespread blistering of the skinThickened, leathery skinIntense itchingSkin flushing or rednessSwelling of the skin when rubbed (Darier sign)Yellowish-brown or reddish skin patchesAbdominal painDiarrheaNausea and vomitingRapid heartbeatLow blood pressure episodesSevere allergic-type reactions (anaphylaxis)Skin that blisters easily with minor frictionIrritability in infantsHeadaches
Clinical phenotype terms (7)— hover any for plain English
Sporadic
Usually appears on its own, not inherited from a parent
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for Bullous diffuse cutaneous mastocytosis.
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Specialists
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Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Bullous diffuse cutaneous mastocytosis.
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Questions for your doctor
Bring these to your next appointment
- Q1.How severe is my child's condition, and what is the expected course over time?,What specific triggers should we avoid, and how do we manage accidental exposures?,When and how should we use the epinephrine auto-injector?,Are there any medications or vaccines my child should avoid?,Should my child have a bone marrow biopsy to check for systemic involvement?,How often should serum tryptase levels and other blood tests be monitored?,What should we tell schools, daycare providers, and other caregivers about this condition?
Common questions about Bullous diffuse cutaneous mastocytosis
What is Bullous diffuse cutaneous mastocytosis?
Bullous diffuse cutaneous mastocytosis (BDCM) is a rare and severe form of mastocytosis that primarily affects infants and young children. In this condition, mast cells — a type of immune cell normally found in small numbers in the skin — build up in large amounts throughout the skin. This leads to widespread skin involvement with blistering (bullae), thickened skin, and intense itching. The blisters can be large and may break open, leaving raw, painful areas that are at risk for infection. Mast cells contain chemicals like histamine that, when released in excess, can cause flushing, low bloo
How is Bullous diffuse cutaneous mastocytosis inherited?
Bullous diffuse cutaneous mastocytosis follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Bullous diffuse cutaneous mastocytosis typically begin?
Typical onset of Bullous diffuse cutaneous mastocytosis is neonatal. Age of onset can vary across affected individuals.