ObjectiveTo summarize the incidence and clinical features of drug hypersensitivity reactions in children treated with sustained-releasing gonadotropin-releasing hormone agonists （GnRHa）， aiming to provide guidance for the safe clinical application of GnRHa in children. MethodsThe medical data of children diagnosed with central precocious puberty （CPP） or early and fast puberty （EFP） were retrospectively analyzed， who received GnRHa treatment at the Children's Growth Center of the First Affiliated Hospital of Sun Yat-sen University between January 1990 and July 2023. The occurrence of GnRHa-related drug hypersensitivity reactions were summarized， including the incidence and clinical features of systemic reactions and sterile abscesses. ResultsAmong the 1 684 children treated with GnRHa for CPP/EFP， the female-to-male ratio was 3.8∶1. A total of nine children （0.53%） developed 44 occurrences of drug hypersensitivity reactions. Four children （0.24%） presented with sterile abscesses （21 occurrences）， and five children （0.30%） experienced systemic hypersensitivity reactions （14 occurrences）. Four children were hypersensitive to triptorelin acetate， three were hypersensitive to leuprorelin acetate， and two were hypersensitive to both triptorelin acetate and leuprorelin acetate. The predominant hypersensitivity reactions to leuprorelin acetate were sterile abscesses， observed in four cases （4/277， 1.44%）， whereas the main reactions to triptorelin acetate were systemic hypersensitivity reactions， affecting five cases （5/1 501， 0.33%）. Case one presented with a severe and complex condition， exhibiting hypersensitivity to multiple GnRHa preparations （sustained-releasing triptorelin， sustained-releasing leuprorelin， and short-acting triptorelin）， and presenting with diverse manifestations， including induration， sterile abscesses， systemic hypersensitivity reactions， and even loss of suppression of the hypothalamic-pituitary-gonadal axis， leading to treatment failure. ConclusionsThe proportion of children experiencing drug hypersensitivity reactions to sustained-releasing GnRHa is relatively low at 0.53%， with diverse manifestations. The reactions primarily manifest as sterile abscesses and systemic hypersensitivity reactions， and in severe cases， may lead to treatment failure due to loss of suppression of the hypothalamic-pituitary-gonadal axis.

ObjectiveTo sum up the clinical features of 5α-reductase type 2 deficiency （5α-RD2） complicated by central precocious puberty （CPP）， and provide experience for clinicians. MethodsA retrospective review was conducted of child patients with 5α-RD2 followed up to puberty at a single tertiary pediatric center， in whom 6 cases developed CRP. Clinical characteristics and treatment history of them were analyzed. A literature review was also performed to investigate possible mechanisms underlying the co-occurrence of 5α-RD2 and CPP. ResultsThe median age at initial presentation was 5.55 years （IQR 3.50-7.20）. Common clinical features included micropenis and hypospadias. Median stretched penile length （SPL） was 2.25 cm （IQR 1.8-2.8）， with an SPL-SDS of -4.5 （IQR -3.1 to -5.8）. Median external masculinization score （EMS） and Prader scores were 8.5 （IQR 5.0-9.0） and 4.5 （IQR 3.0-5.0）， respectively. Pubertal onset occurred at a median age of 8.70 years （IQR 7.80-9.00）. Three patients were overweight or obese. Five had received 2.5% dihydrotestosterone （DHT） gel prior to pubertal onset， with a median cumulative dose of 205.5 mg/kg （IQR 72.0-660.3 mg/kg） with DHT gel therapy. Notably， one patient with normal body mass index （BMI） and no history of androgen or gonadotropin therapy also exhibited early pubertal onset at 8.4 years. ConclusionCPP in children with 5α-RD2 may be associated with prior dihydrotestosterone （DHT） gel therapy and elevated BMI； however， a potential intrinsic link to the underlying disorder cannot be excluded. Further studies are needed to elucidate the pathophysiological mechanisms.