Localised vulvar and perianal pruritus as the first manifestation of Type 1 diabetes mellitus in a young woman

Abstract

Itching is an unpleasant sensation that induces the desire to scratch. It usually appears due to a cutaneous disorder, but in a high percentage of the affected individuals it represents a manifestation of a systemic disease, such as lymphoproliferative, endocrinological or neurological disorders. In this article, we report an unusual case of persistent vulvar and perianal pruritus in a teenager that led to the diagnosis of Type 1 diabetes mellitus, and its spontaneous resolution after normalisation of blood glucose levels. A 15-year-old Spanish Caucasian woman with no relevant past medical history presented with pruritus located in the vulvar and perianal area for several months. She had been treated with multiple treatments including topical and oral corticosteroids and oral antihistamines with poor disease control. The itching was persistent, predominantly at night and affected her quality of life. A complete physical examination was performed without significant findings, except for some dispersed excoriations in the external vulvar and perianal area. Body mass index was 21. Given the persistence of symptoms, a general blood analysis was performed, including blood count, iron, thyroid and liver profiles, as well as serum bile acids. Blood analysis was normal except for high blood glucose (8.88 mmol/L). For this reason, the patient was referred to the hospital’s endocrinology department for an evaluation. After a series of tests with altered results, including oral glucose tolerance test and HBA1c, the patient ended up being diagnosed with Type 1 diabetes. Insulin treatment was prescribed with blood glucose normalisation and curiously after 6 months of follow up the patient presented a complete disappearance of vulvar and perianal pruritus. Located vulvar or perianal pruritus is a rare phenomenon. It usually gets worse at night, and repeated scratching can cause lichenification. It can be primary or idiopathic when there is no identifiable skin disorder or secondary. In the particular case of perianal pruritus, secondary causes include chronic diarrhoea, haemorrhoids, anal fissures, infestations and certain skin disorders such as contact eczema or psoriasis. Moreover, in the case of vulvar pruritus, its secondary causes include candidiasis, contact eczema, lichen sclerosus or Paget disease, among others. All these diseases were carefully excluded in our patient. Generalised pruritus may be a symptom of diabetes mellitus. However, persistent pruritus located in the genital area is a rare manifestation. There are few studies in the literature that refer to this association. An interesting study that analysed the frequencies of local and generalised pruritus among persons with diabetes and healthy controls found a significantly higher proportion of vulvar pruritus in persons with diabetes versus healthy controls. Furthermore, it appears that pruritus is greater if there is poor glycaemic control. In addition to the most well known causes of genital pruritus, physicians should include poorly controlled diabetes as a possible cause of localised genital pruritus. Therefore, it would be advisable to include blood glucose in the diagnosis of genital pruritus in patients where there is no other possible identifiable cause.