Seven years old is pretty young, but there are published reports of use on children (see below).
As you note, the long-term effects are undetermined, since this has only been widely available since about 1997.
Using sunscreen is critical, especially with a child that age.
I wouild strongly urge you to coordinate any treatment with a dermatologist.
J Clin Laser Med Surg. 2000 Dec;18(6):277-80.
Hair removal using the long-pulsed ruby laser in children.
Morley S, Gault D.
Department of Plastic Surgery, Restoration of Appearance and Function Trust, Mount Vernon Hospital, Northwood, Middlesex, UK. S.Morley@beatson.gla.ac.uk
OBJECTIVE: The purpose of this study was to assess the efficacy of laser assisted hair removal in children aged 16 and under using the long pulsed ruby laser. BACKGROUND DATA: Unwanted hair in the pediatric population can be due to congenital hairy nevi and hypertrichosis. Methods of effecting hair removal include shaving, electrolysis, and laser depilation. The long-pulsed ruby laser is an established treatment modality in adults, but its use specifically in children has not been investigated. METHODS: Patients aged 16 or under undergoing treatment with the ruby laser for unwanted hair were assessed. Hair counts were determined before and after treatment and an assessment of overall satisfaction was made using a parental questionnaire. RESULTS: Treatment was regarded as successful in 25 out of 28 cases where there was a clear reduction in hair growth at the site treated with an average fall in hair count of 63% at 6 months follow up. There was no scarring or hyperpigmentation in this group and no serious complications. Total suppression of hair growth was not permanent but usually lasted between 3 and 6 months. Few problems were encountered from using the technique specifically in children, and pain was well controlled in most cases. CONCLUSIONS: We would recommend the long-pulsed ruby laser as a useful form of hair removal in children that is quick, simple and well tolerated. At present, the technique leads to hair loss that is temporary but most patients and their parents feel the treatment gives worthwhile benefits.
PMID: 11572220 [PubMed - indexed for MEDLINE]
Arch Dermatol. 2001 Jul;137(7):877-84.
Primary generalized and localized hypertrichosis in children.
Vashi RA, Mancini AJ, Paller AS.
Division of Dermatology, Children’s Memorial Hospital, 2300 Children’s Plaza-107, Chicago, IL 60614, USA.
OBJECTIVE: To review the causes, presentation, and therapy of primary generalized and localized symmetrical hypertrichosis in children. DESIGN: Retrospective medical record review. SETTING: Academic specialty referral clinic for pediatric dermatological disorders. PATIENTS: Case series of 11 prepubertal male and female patients who had idiopathic hypertrichosis between July 1, 1990, and November 30, 1999. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Clinical distribution of increased hair growth and types of hair removal methods used. RESULTS: Seven girls and 4 boys, ranging in age from 4 months to 11 years, were evaluated. Four patients showed generalized hypertrichosis. The other 7 patients had localized symmetrical hypertrichosis, representing the subsets of hypertrichosis cubiti, anterior cervical hypertrichosis, posterior cervical hypertrichosis, and faun tail deformity. All patients with generalized hypertrichosis manifested the condition at birth; the age of onset in children with localized symmetrical primary hypertrichosis ranged from birth to 4 years. One girl with generalized hypertrichosis had gingival hyperplasia and the girl with faun tail deformity had bony diastematomyelia with spina bifida occulta. The medical histories and physical examination findings of all of the children were otherwise unremarkable. All patients were referred for diagnostic and therapeutic considerations. CONCLUSIONS: Primary hypertrichotic conditions, whether localized or generalized, are rare in pediatric patients and of unknown origin. Although otherwise benign, these disorders may result in cosmetic disfigurement and psychosocial trauma for patients and families. Patients and their families should be adequately advised of the available treatment methods for both temporary and permanent hair removal.
PMID: 11453806 [PubMed - indexed for MEDLINE]