The skin is the body’s largest organ and should not be assessed in isolation from general health. Sleep routine, nutrition, the course of blood sugar, thyroid function, and iron and B12 status are assessed together with certain changes seen in the skin. This does not mean that the cause of a skin complaint always lies in one of these factors.
In people who present with complaints such as dullness or dryness of the skin, hair loss or brittle nails, the assessment sometimes focuses on the skin alone. Yet these complaints may also be seen alongside the areas addressed in an internal medicine consultation.
The assessment of a skin complaint is not limited to the skin. This does not mean that an assessment directed at the skin is unnecessary; the skin assessment and the metabolic assessment complement each other.
What is assessed alongside the skin
Sleep routine. Sleep duration and quality are general health factors that affect the repair processes of many tissues, including the skin. Frequent waking at night, snoring and daytime drowsiness are also asked about.
Eating routine. For adults, the World Health Organization (opens in a new tab) recommends at least 400 grams of vegetables and fruit a day, free sugars below 10% of daily energy intake, salt below 5 grams a day, and saturated fat at no more than 10% of total energy intake. These are general health recommendations, not recommendations directed at the skin.
The course of blood sugar. Where blood sugar runs high, dryness of the skin, itching and delayed wound healing may be seen.
Thyroid function. Thyroid hormones running lower or higher than expected may be seen together with dryness of the skin, hair loss and changes in the nails.
Iron, B12 and vitamin D status. These are assessed together with complaints of fatigue and hair loss.
Body weight. According to the results of the Türkiye Nutrition and Health Survey-2017, the General Directorate of Public Health (opens in a new tab) of the Ministry of Health of the Republic of Türkiye reports the prevalence of obesity in those aged over 15 as 31.5%, and states that obesity increases the risk of type 2 diabetes, hypertension and metabolic syndrome.
Current medication and supplements. Some medicines may lead to changes in the skin.
What is asked at the consultation?
- The course of the complaint. When it began, and its relationship to the season or to a particular period.
- Sleep and eating routine. The number of meals, the intervals between them, and the duration and quality of sleep.
- Accompanying symptoms. Fatigue, weight change, menstrual pattern, constipation, feeling cold.
- Current medication and supplements.
- Measurements and laboratory tests. Where necessary, a full blood count, iron and ferritin, B12, thyroid function tests and blood sugar are assessed.
In which patients is it assessed differently?
In the situations below, the assessment proceeds differently.
- In patients who are pregnant or breastfeeding (changes specific to these periods may be seen in the skin; any adjustment to the eating routine is made separately)
- In patients with a known skin disease (follow-up falls within the dermatology specialty, and this assessment does not replace it)
- In patients with a history of an eating disorder (dietary recommendations are adjusted accordingly; restrictive recommendations may not be appropriate)
- In patients with kidney or liver disease (adjustment to the eating routine is planned separately)
- In patients receiving active oncological treatment (follow-up falls within the relevant specialty)
- In patients under 18 years of age (assessment lies within the field of paediatrics; this content has been prepared for adults)
Points to be aware of
Not every change in the skin can be attributed to a metabolic cause. A skin lesion that is new, growing, or changing in colour or border requires a dermatology assessment. This article does not replace that assessment.
Adjusting the eating routine is not a skin treatment. The points above are general health recommendations; they do not mean that a particular result for the skin will be achieved.
Do not start a supplement on your own. Unnecessary use of products recommended for the skin and hair provides no benefit and may interact with your current medication.
The time it takes for an effect to appear varies from person to person. Changes to sleep and eating routine are generally reflected over a period of weeks to months.
Results vary from person to person.
When should you see a physician without delay?
If you notice these symptoms, consult a physician without delay:
- Spots or moles on the skin that are new, growing or changing in colour
- A widespread rash or itching
- Wounds that heal slowly
- Marked and rapid hair loss
- Dryness of the skin seen together with fatigue, weight change and feeling cold
- Yellowing of the skin or of the whites of the eyes
If a widespread rash is accompanied by shortness of breath, swelling of the face or tongue, or fever, go directly to the emergency department.
Frequently asked questions
Does a change in eating routine show in the skin?
No such outcome can be stated in advance. Sleep and eating routine affect general health, and they are assessed together with certain changes seen in the skin. However, the cause of a skin complaint may also lie outside these areas; the distinction is made at the consultation.
When should I see a dermatologist?
If there is a skin lesion that is new, growing or changing in colour, a dermatology assessment is required. If a skin complaint is accompanied by fatigue, weight change, hair loss and menstrual irregularity, an internal medicine assessment is also performed. Neither replaces the other.
Which tests are looked at for a skin-related complaint?
There is no standard list. Depending on the complaint, a full blood count, iron and ferritin, B12, thyroid function tests and blood sugar are generally assessed. Which of these are needed is determined at the end of the consultation.
Should I take a supplement for hair loss?
Starting one without a physician’s assessment is not recommended. Taking a supplement when no deficiency has been demonstrated does not provide the expected benefit and may interact with your current medication. Tell your physician about every product you use.
Is drinking plenty of water enough for the skin?
Adequate fluid intake is recommended for general health, but it cannot be presented as a solution for the skin on its own. Sleep, eating routine and any underlying metabolic factors are assessed together.
Does my sleep routine really affect my skin?
Sleep is a general health factor that affects the body’s repair processes, which is why it is also asked about in people who present with a skin complaint. However, it cannot be said that sleep routine alone is decisive; it is assessed together with the other factors.
Sources
- World Health Organization, Healthy diet fact sheet, 26 January 2026. https://www.who.int/news-room/fact-sheets/detail/healthy-diet (opens in a new tab)
- Ministry of Health of the Republic of Türkiye, General Directorate of Public Health, Obezite (data from the Türkiye Nutrition and Health Survey-2017). https://hsgm.saglik.gov.tr/tr/obezite (opens in a new tab)
