Indolent Systemic Mastocytosis

Symptom-focused management of slowly progressive systemic mastocytosis.

Written by: Saygı Hospital Health Guide Editorial Board

Last updated: June 9, 2026

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Dahiliye (İç Hastalıkları) department. Book Appointment →

What is Indolent Systemic Mastocytosis?

Indolent systemic mastocytosis (ISM) is the most common subtype of systemic mastocytosis with the best prognosis. Patients do not have organ dysfunction criteria (C findings).

Clinically, urticaria pigmentosa, anaphylaxis, flushing, abdominal pain, diarrhea, and osteoporosis are prominent. It significantly affects quality of life.

Treatment is entirely based on symptomatic and proactive protection. In recent years, avapritinib has received FDA approval for ISM, providing an option to reduce the symptom burden.

Symptoms

Urticaria pigmentosa

Sudden flushing and dermographism

Anaphylaxis attacks

Abdominal pain and diarrhea

Headache and fatigue

Osteoporosis and bone pain

Psychiatric symptoms

Risk Factors

Adult-onset mastocytosis

Baseline tryptase between 20-200

KIT D816V positivity

Urticaria pigmentosa skin findings

Hymenoptera allergy

Family history of mastocytosis

Stress and trigger exposure

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

Recurrent anaphylaxis
Unexplained urticaria and flushing
Early-age osteoporosis
Unexplained GI symptoms
Tryptase elevation
Increased sensitivity to triggers

Treatment Methods

Combined H1/H2 antihistamine therapy

Cromoglycate and leukotriene antagonist

Avapritinib for symptom control

Osteoporosis treatment with bisphosphonates

Epinephrine pen for anaphylaxis

Education on trigger avoidance

Stress and psychosocial support

Regular tryptase and bone follow-up

Which Department to Visit?

You can visit our Dahiliye (İç Hastalıkları) department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

Learn About Dahiliye (İç Hastalıkları) Department

Let us help you

You can make an appointment with our specialists or contact us for your concerns.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.