The Role of Mast Cells in Health and Disease: Part 3

Exploring the Overlap of Mast Cell Activation Syndrome (MCAS) and the Ehlers-Danlos Syndromes (EDS)

Mast Cell Activation Syndrome (MCAS) and Ehlers-Danlos Syndromes (EDS) are two distinct yet interconnected medical conditions that share a complex relationship. MCAS involves the over-activation of mast cells, leading to allergic symptoms, while EDS encompasses a group of genetic connective tissue disorders characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. Let’s talk about the overlap between MCAS and EDS, exploring their relationship, potential mechanisms, and implications for diagnosis and treatment.

The Clinical Overlap

MCAS and EDS have a notable clinical overlap. However, the true prevalence of these combined conditions is hard to estimate due to hurdles in care and diagnosis. Studies suggest that MCAS may occur in 24-66% of EDS patients. Joint hypermobility also has a clinical overlap with conditions involving mast cells, such as asthma.

A Genetic or Biological Link?

Despite the clinical overlap, the precise relationship between MCAS and EDS remains a subject of ongoing research. Several theories attempt to explain this connection:

1. Genetic Link: There may exist an undiscovered genetic link that contributes to the co-occurrence of MCAS and EDS. A shared genetic factor or factors could potentially underlie the development of both conditions in some individuals.

2. Connective Tissue Changes: EDS-related changes in connective tissue could create an environment that encourages mast cell over-activation and increase their susceptibility to degranulation. In this scenario, MCAS may be a consequence of EDS-related tissue fragility and laxity.

3. Mast Cell Regulation: Alternatively, mast cells might play a role in regulating connective tissue homeostasis. Dysregulated mast cell activity could contribute to the development or severity of EDS symptoms.

It's important to note that these theories are speculative and require further investigation.

MCAS Across EDS Subtypes

While research has predominantly focused on hypermobile EDS (hEDS) and Hypermobile Spectrum Disorder (HSD), anecdotal reports within the EDS community suggest that MCAS could affect other EDS subtypes as well. However, more research is needed to understand the prevalence and impact of MCAS across all EDS subtypes.

Mast Cells and EDS Symptoms

Mast cells reside in connective tissue throughout the body, contributing to various conditions even in individuals without EDS. While they have not been directly implicated in causing joint hypermobility or ligament laxity seen in EDS, they can play a role in wound healing and injury recovery. EDS patients' susceptibility to orthopedic injuries, delayed wound healing, and tissue damage suggests that uncontrolled MCAS could potentially exacerbate symptom severity and comorbidities.

Effect of MCAS Treatment on EDS Symptoms

Effectively managing MCAS can lead to symptom improvement and alleviate some comorbidities in EDS patients. However, there is currently no evidence to suggest that MCAS treatment directly influences EDS symptoms or stabilizes connective tissue. While MCAS management may enhance the overall quality of life for EDS patients, it does not offer a cure for the underlying EDS condition itself.

Seeking a Diagnosis

Given the clinical overlap between MCAS and EDS, many healthcare professionals recommend evaluating patients for both conditions when either is suspected. For some patients, this may involve consulting different specialists as not all physicians have experience with MCAS and EDS

While there are many theories, the exact mechanisms underlying the overlap remain elusive. On a personal note, I am interested in studying the interplay between these two conditions and look forward to hopefully sharing research in this space in the future.

See the post on Instagram here.

For more reading - check out this excellent review article.

(Note: This blog post is a general overview and does not constitute medical advice. Consult a healthcare professional for personalized guidance and treatment.)