Clinical presentation of scabies from 1996 to 2022: a retrospective cohort study from Finland.

Background: Increasing numbers of scabies cases have been reported in Europe and around the world in recent years. Scabies is more common in children and adolescents than in adults.

Objectives: To characterise patient profiles and treatment strategies of scabies over time at the dermatology clinic of Oulu University Hospital (OUH), Finland.

Methods: The OUH database was searched using diagnostic codes, and all patients diagnosed with scabies in the OUH dermatology unit between 1996 and 2022 were included in the study. The retrieved patient records were reviewed for demographic and clinical data.

Results: The study included the records of 662 patients. 'Suspected scabies' was given as reason for referral to a specialist care in only 21.5% of cases. Time between a symptom onset and the referral to the dermatology unit was significantly longer in adults and adolescents than in small children (p < 0.001), and was longer than six months in one-fifth of adults. Symptomatic sites varied between age groups: compared with small children, adults more commonly (p < 0.001) presented with symptoms in the genital-gluteal area, whereas symptoms were located on the head and 'foot and ankles' more often in young children than other age groups (p < 0001 for all comparisons).

Conclusions: Diagnosis was markedly delayed in many patients, especially adults. Unspecified, pruritic skin symptoms should lead to a suspicion of scabies, and when a diagnosis is unclear, the patient should be referred to a dermatologist as quickly as possible. This would both help patients and prevent further spread of the infestation.