The goal of this observational cohort study is to investigate the effect of intense pulsed light (IPL) for excessive hair in patients >18 years of age and in need of gender affirmative treatment, refered to the department of dermatology and venereology, Umeå University Hospital, Sweden. The main questions this study aims to answer are:

• [To evaluate the effect of consecutive IPL treatments in women with hirsutism due to polycystic ovarial syndrome (PCOS), with or without anti-androgen treatment]
• [To evaluate the effect of consecutive IPL treatments in individuals born as biologically men but in transition to become women, with or without hormonal treatment].

Patients will use self-assessed questionnaires evaluating:

• Background characteristics and time spend on concealing, reducing and treating hypertrichosis at home.
• Ferriman-Gallwey scale, regarding the intensity of their hypertrichosis.
• Dermatology Life Quality Index (DLQI) for quality of life Patients will be recruited consecutively and assessed at each visit, at the clinic before the treatments, ranging from baseline to a minimum of 5 treatment sessions.Since this is an observational study, all patients are treated by others than the researchers according to the routines och the clonic and there will be no other groups to compare the patients with.

Background Hypertrichosis is defined as excessive hair in men and women while the term hirsutism is used for women with increased hair count due to hormonal changes such as increased levels of androgens. Hypertrichosis can be focal och general and hereditary or acquired. In hereditary hypertrichosis, genes or in uterus exposure to certain medications have been suggested as causes for the condition. In acquired cases, the hypertrichosis is often triggered by hormonal changes due to different medical conditions.

Investigating the cause of hypertrichosis is done by examining the patient's medical history and a complete examination of the skin. An often-used tool, for severity assessment of hypertrichosis is Ferriman & Gallwey scale. This international scale is used both by clinicians and patients for both research and in clinical practice. The Ferriman & Gallwey scale investigate 9 parts of the body with each part visually described with increasing density of hair as 4 pictures ranging from 0 point (no hair) to 4 points (dense hair). According to Ferriman & Gallwey scale, a total of ≥8 points in white and black, ≥9-10 points for mediterranean, south american and middle eastern, and ≥2 points for east Asian women indicate hypertrichosis.

Hirsutism is a common feature in women with Polycystic Ovarian Syndrome. The increased density of hair becomes noticeable during puberty and affected women report a great negative impact from the condition on their quality of life. Signs of depression and anxiety are common in women with hirsutism, due to increased social isolation and remarks regarding the hair growth and its colour by their surroundings.

Individuals with gender dysphoria and in transition of gender reassignment from the biological male sex to female, are sometimes prescribed estrogen or anti-androgens to decrease male characteristics on their body. Feminizing hormone therapy for male-to-female gender dysphoria aim to minimize body and facial hair growth. In women with mild hirsutism, there is evidence that oral contraceptives and anti-androgen treatment could be beneficial against hair growth on the body. However, the effects of these medications together with other methods such light-based treatments as intense pulsed light or lasers have not been evaluated. Intense Pulsed Light (IPL) which transmit light as energy to become absorbed as heat in the hair follicle. Repeated treatments are necessary to obtain a significant reduction of hair and long-term effects of IPL in reducing hair varies. Theoretically, the combination of anti-androgens and estrogen together with IPL, should have a synergetic effect in hair reduction no matter the intention for hair reduction. Thus, the aim of this study is to evaluate the effects of IPL, in patient with hirsutism/hypertrichosis, with or without hormonal therapy, regarding hair reduction and potential impacts on quality of life.

Materials and methods Study design Observational Cohort study Patients Patients with hirsutism and gender dysphoria are medically treated and have their follow-ups by other specialities than dermatology. However, the laser clinic at the department of dermatology and venereology, Umeå university hospital receives referrals from other departments across northern Sweden for reducing body hair in these patients. Consecutive patients referred to the department of dermatology and venereology at Umeå University Hospital due to hypertrichosis will be assessed according to our inclusion and exclusion criteria.

Inclusion criteria:18 years of age and above, diagnosis of PCOS obtained by a gynaecologist and hirsutism, diagnosis of gender dysphoria obtained after psychiatric evaluation, ≥3 points in hair density according to Ferriman-Gallwey scale on a specific part of the body. Exclusion criteria: Language barrier causing problem in understanding questionnaires or not being able to give consent, hair colours of white, orange or grey hair, skin type 5 and above according to Fitzpatrick and hereditary hypertrichosis.

Data collection The procedure of hair reduction by light based methods are done primarily by nurses and it is only in case of complications a physician is advised. Data will be collected by a coded, pre-treatment hypertrichosis specific questionnaire, asking about participants background, medical history, current medication, subjective assessment of hair density according to Visual Analogue Scale (VAS-10 point scale), localisation of hypertrichosis, Ferriman-Gallwey scale and Dermatology Life Quality Index (DLQI). DLQI is a health questionnaire for dermatology consisting of 10 questions. DLQI investigates quality of life, the duration of one week back in time. A total of 0-30 points can be yielded from the questionnaire and the more points gained, is interpreted as more negative impacts on quality of life. At each follow-up (3 months interval) the participants will be asked to fill in the questionnaire and data from a total of 5 follow-ups will be collected. All patients will be treated by nurses at the clinic, with IPL (Intense pulsed light) Nordlys by Ellipse, using a 645- to 950-nm cut off filter. Data regarding dose, wavelength and number of pulses given at each treatment session will be collected. This data is recorded and saved inside the IPL machine.

Ethical considerations All patients will be asked for their oral and written consent after receiving information about the research project. Permissions regarding questionnaires used in this study will be obtained prior to the start of the study. An ethical permission to conduct this study will be obtained from the Swedish Ethical Review Board. As this is an observational study, none of the patients will receive any other treatment than they would have for hypertrichosis, at our clinic. Participating in this study does not mean extra visits nor any conveniences for the patients other than filling out coded questionnaires at the beginning of each treatment session. The researchers in this study will not treat any of the patients. All collected data is compiled and analysed at a group level. None of data or patient characteristics will be shared with other people outside the research group and all data will be saved electronically and kept inside in a locked room.

Statistics An estimate of 32 patients is required for the study to have a 80% chance of detecting, as significant at the 5% level, a decrease in the primary outcome measure (DLQI) from 10 points to 7 points. Considering 20% lost of response/inadequate filling of questionnaires will result in a total of 39 patients needed as sample size.

Background characteristics of patients and categorical variables will be tested with Chi-test. Normally distributed and continuous data, expressed as mean and standard deviation, will be tested for significant differences with pair t-test between the treatment sessions. Non continuous data, as median and inter quartile range will be subjected to non-parametric tests such as Mann-Whitney U test. Correlations will be tested by Pearson's correlation coefficient or spearman's rank test. Bivariate logistic regression model will be used to analyse probabilities of medications such as estrogen and anti-androgens as dependent variables, tested for outcome variables such as Ferriman-Galway scale and DLQI. International Business Machines Corporation (IBM), Statistical Package for the Social Sciences (SPSS) software will be used for statistics. A p-value less ≤ 0.05 is considered statistically significant.

Inclusion Criteria:

• 18 years of age and above
• Diagnosis of PCOS obtained by a gynaecologist and hirsutism,
• Diagnosis of gender dysphoria obtained after psychiatric evaluation,
• ≥3 points in hair density according to Ferriman-Gallwey scale on a specific part of the body

Exclusion Criteria:

• Language barrier causing problem in understanding questionnaires or not being able to give consent
• Hair colours of white, orange or grey hair
• Skin type 5 and above according to Fitzpatrick
• Hereditary hypertrichosis

Patients with hirsutism and gender dysphoria are medically treated and have their follow-ups by other specialities than dermatology. However, the laser clinic at the department of Dermatology and Venereology, Umeå university hospital receives referrals from other healthcare departments, across northern Sweden, for body hair reduction. Consecutive patients referred to the department of dermatology and venereology at Umeå University Hospital due to hypertrichosis will be assessed according to our inclusion and exclusion criteria.

According to Swedish Law no patient data can be transferred or shared outside the location where the research is conducted. However, data on a group level can be shared upon reasonable request.