New quality of life scales capture what pediatric mastocytosis really costs children and parents

Children with cutaneous mastocytosis and their parents finally have a measurement tool built for their disease. In a preliminary validation study conducted at two specialized tertiary centers in Turkey, researchers developed and tested two disease-specific quality of life questionnaires: the Pediatric Mastocytosis Quality of Life scale, known as PedMQLS, completed by children aged 6 to 18, and a parallel parent version called PedParentMQLS, completed by the parent mainly responsible for the child’s daily care. According to the study published in Allergy, Asthma & Clinical Immunology, both 14-item instruments proved reliable enough to distinguish how mastocytosis weighs on social functioning and emotional well-being, filling a gap that generic dermatology questionnaires have left open for decades.

Mastocytosis is a rare disease driven by clonal proliferation of mast cells in the skin, bone marrow and various internal organs. The World Health Organization divides it into two main categories: cutaneous mastocytosis and systemic mastocytosis. The systemic form appears mainly in adulthood and involves organs beyond the skin, while the cutaneous form develops mostly during childhood, particularly in infancy, and usually regresses spontaneously during adolescence while remaining confined to the skin. In adults, the disease significantly affects emotional and social functions and reduces quality of life, and a disease-specific questionnaire called the MC-QoL exists for that population. Children, by contrast, have been assessed mainly with the Children’s Dermatology Life Quality Index, a 10-item tool developed in 1995 that measures how skin disease in general disrupts daily life.

The problem, the researchers argue, is that the CDLQI does not adequately capture what makes mastocytosis distinctive: its specific triggers, systemic symptoms, and the concerns that parents carry. Disease-specific instruments, they note, provide more sensitive and clinically meaningful data than generic scales. To build one, the team followed recommendations for designing patient-reported outcome measures. Because formal focus-group interviews were not feasible given the rarity of pediatric mastocytosis, they drew on recurrent concerns reported by patients and parents during routine clinical follow-up, combined with expert opinion and a review of existing literature. That process generated an initial pool of 25 items for each of the two versions.

Refinement came next. The research team reviewed every item against fundamental scale development principles, checking for redundancy and similarity, negatively worded statements, whether each item carried a single judgment, and whether the language was clear and understandable. Items with overlapping meanings were merged and inappropriate statements removed, leaving a 19-item preliminary version of each scale. Each item is answered on a 4-point Likert-type scale ranging from Never, scored 1 point, to Usually, scored 4 points, and the total score is the sum of the item responses. The questionnaires were conceptually designed around two domains of health-related quality of life, social and daily life functioning and emotional well-being, but no predetermined subscale structure was imposed; the final two-factor structure emerged empirically from the data.

Content validity was tested with the Davis technique, in which six experts from pediatric allergy and public health judged the clarity, relevance and comprehensiveness of the draft items. Expert feedback led to the removal of 5 items, and the content validity index of the remaining 14 items reached 0.97, well above the threshold of 0.80 per item that the literature considers adequate. The study cohort comprised 51 children diagnosed with cutaneous mastocytosis, together with their parents, recruited from the pediatric allergy and immunology outpatient clinics of Prof. Dr. Cemil Taşcıoğlu City Hospital and Sakarya University Faculty of Medicine. Diagnosis rested on typical skin lesions, a positive Darier’s sign and the absence of systemic symptoms, with systemic mastocytosis ruled out by clinical and laboratory evaluation. Children over 18, those with comorbid chronic disease, progression to systemic disease, or regular medication use were excluded.

Structural validity was examined through exploratory factor analysis using Principal Axis Factoring with Varimax rotation, after sample adequacy was confirmed with the Kaiser–Meyer–Olkin measure and Bartlett’s test of sphericity. For the child version, the analysis yielded a two-factor structure with eigenvalues above 1 that explained 48.5 percent of total variance, with the social life and functioning factor accounting for 28.3 percent and the emotions factor 20.02 percent. The parent version showed a stronger structure, explaining 63.05 percent of total variance, with 35.19 percent attributable to social life and functioning and 27.86 percent to emotions. Factor loadings were moderate to high and stronger in the parent form. A few items, including items 1, 3 and 14 of the child scale and item 14 of the parent scale, showed negative factor loadings but were retained as clinically meaningful based on expert opinion.

Reliability results split along the same line. The parent scale showed high internal consistency with a Cronbach’s alpha of 0.909 overall, reaching 0.875 for the social life and functioning subscale and 0.781 for the emotions subscale. The child scale reached an overall alpha of 0.785, which the authors describe as acceptable, though the subscale values were lower, at 0.654 for social life and functioning and 0.598 for emotions, a shortfall they attribute to the limited sample size. The original Turkish versions were also translated into U.S. English by two independent translators, with backward translation by a bilingual native speaker and final approval after comparison with the original and expert review, making the instruments available beyond Turkey.

The scores themselves tell a clinical story. The mean total PedMQLS score was 20.6 plus or minus 5.2, with a median of 19, while the parent version averaged 25.4 plus or minus 7.4, with a median of 24; higher scores indicate greater impairment. Scale scores tracked several disease features. In children, the social life subscale differed significantly by the presence of flushing, trauma as a triggering factor, venom exposure and SCORMA disease severity scores, while the emotional subscale differed by flushing, gastrointestinal symptoms, SCORMA scores and the regression type of the disease. Total child scores differed significantly with flushing, gastrointestinal symptoms, trauma, venom exposure and SCORMA score. In parents, total scores rose significantly with the child’s current age, swelling of lesions, pruritus, flushing, gastrointestinal symptoms, heat or fever as a trigger, trauma, a lesion count above 50, regression type and SCORMA score. Notably, the number of lesions did not affect children’s own quality of life scores but had a significant impact on parents’ scores across social functioning, emotional well-being and overall totals, and trauma emerged as a major trigger associated with deterioration in quality of life.

Convergent validity was assessed by correlating the new scales with the established anchors. The PedMQLS total score correlated strongly with the CDLQI at r = 0.85, with the social life subscale at r = 0.80 and the emotional subscale at r = 0.71, all statistically significant. The PedParentMQLS total score correlated strongly with the Family Dermatology Life Quality Index at r = 0.75, as did its social life subscale, with the emotional subscale at r = 0.66. Correlations between the child and parent versions of the new scales were more modest, with the child total correlating with the parent total at r = 0.49, a pattern the authors say indicates consistency between child-reported and parent-reported impairment while also hinting at perceptual differences that the small sample could not fully clarify. Laboratory parameters mostly stayed within reference ranges and showed no significant correlation with the scales, although exploratory negative correlations appeared between LDH and the child emotional subscale, tryptase and the CDLQI, and vitamin D and the child emotional and total scores; the authors caution these should be read as statistical associations rather than evidence of clinically meaningful biochemical abnormalities.

The authors are explicit that this is a preliminary, cross-sectional validation with a limited sample. The instruments were developed specifically for pediatric cutaneous mastocytosis and do not apply to systemic mastocytosis or hereditary alpha-tryptasemia, comparisons across age bands from 6 to 10, 11 to 15 and 16 to 18 years could not be performed, and the frequent spontaneous regression of cutaneous disease during adolescence may limit practical use to a narrower age range. The cross-sectional design prevents evaluation of how quality of life changes over time, and minimal clinically important difference analysis was not performed. Even so, the team describes the work as the first to investigate quality of life and its determinants in pediatric patients with mastocytosis, and multicenter longitudinal studies with larger cohorts are planned to test responsiveness and clinically meaningful change thresholds. For families navigating a visible, unpredictable skin disease, the message is concrete: the burden is now measurable, in the child’s own words and in the parent’s.

Subject of Research: Development and validation of disease-specific quality of life scales for pediatric cutaneous mastocytosis

Article Title: Development and validation of a quality of life scale for pediatric mastocytosis

Article References: Topçak, A. B., Tüsüz Önata, E., Genç, Ş., Kökcü Karadag, S. I., Çalışkan, N., Yıldırım, G., Boloğur, H., Güngör, H., Karaca Şahin, M., Erbay, M. F., Şarman, H. T., Terzi, Ö., Kocatürk, E., Siebenhaar, F., Özdemir, Ö., & Özçeker, D. (2026). Development and validation of a quality of life scale for pediatric mastocytosis. Allergy, Asthma & Clinical Immunology, 22(1), Article 43. https://doi.org/10.1186/s13223-026-01051-z

Image Credits: AI Generated

DOI: 10.1186/s13223-026-01051-z

Keywords: pediatric mastocytosis, cutaneous mastocytosis, quality of life, PedMQLS, PedParentMQLS, psychometric validation, Cronbach's alpha, exploratory factor analysis, CDLQI, FDLQI, SCORMA index, patient-reported outcomes