D2.230 - Flushing in a Child with Solitary Cutaneous Mastocytoma: A Case Associated with Sesame Allergy

Introduction:Pediatric mastocytosis cases are usually of the cutaneous type. The diagnosis of solitary cutaneous mastocytoma is primarily clinical and is based on lesion morphology, a positive Darier’s sign, and the absence of systemic involvement. Sesame allergy is uncommon in children.

Objective:Here, we present a case diagnosed with solitary cutaneous mastocytoma accompanied by sesame allergy.

Case Report:A 15-month-old boy was admitted with complaints of pruritus and daily episodes of flushing for the past month. The history revealed the appearance of a rash on the right lateral scapular region one month earlier, coinciding with the onset of his symptoms. On admission, a solitary, elevated, hyperpigmented, erythematous, approximately 0.5 × 0.5 cm bullous lesion was observed on the right lateral scapula (Figure 1). There was no organomegaly, and the remainder of the physical examination was normal. Darier’s sign was positive, supporting the diagnosis of solitary cutaneous mastocytoma. Serum tryptase level was 4.9 ng/mL.

The history also revealed that three months prior, the patient developed generalized urticarial rash within 20 minutes of ingesting one teaspoon of tahini, which resolved with antihistamine treatment. There was no history of anaphylaxis. Skin prick testing showed sesame reactivity of 6 × 5 mm, and serum sesame-specific IgE was 8 kU/L. Sesame elimination was recommended. The family was informed about the conditions, and ketotifen drops were prescribed for use as needed. Avoidance of triggering factors was discussed. Due to the accompanying food allergy, an epinephrine auto-injector was prescribed, and detailed training was provided.

Conclusion:The diagnosis of mastocytoma, which commonly appears during infancy, is based on clinical findings. Among edible seed allergies in children, sesame is the most frequent; however, its prevalence is approximately 0.1%. Notably, the coexistence of sesame allergy with solitary cutaneous mastocytoma in children has not yet been reported in the literature. Clinicians should be aware that these two distinct entities may occur together.