The diagnosis of acne is primarily a clinical process, relying on a visual examination of the skin and a detailed discussion of the patient’s medical history. For most people experiencing common breakouts, blood tests are not a routine part of the evaluation or treatment plan. However, blood work becomes an essential tool when acne presents unusually, fails to respond to conventional therapies, or when specific medications are considered. These tests serve two main functions: diagnosing an underlying internal condition driving the skin problem or safely monitoring a patient undergoing systemic medical treatment. Blood analysis offers insights into potential hormonal imbalances contributing to the persistence or severity of the condition.
Clinical Triggers for Ordering Lab Work
A dermatologist orders lab tests based on specific characteristics in a patient’s history or presentation that suggest an internal cause. Acne that is severe, sudden-onset in adulthood, or resistant to standard treatment often prompts a deeper investigation. This is particularly true for women who experience acne around the jawline and chin, a pattern associated with hormonal fluctuation.
Symptoms suggesting a hormonal imbalance, known as hyperandrogenism, are significant clinical triggers. These include hirsutism (the growth of coarse, dark hair in a male-like pattern) or irregular menstrual cycles. Acne appearing in children younger than ten is also a red flag, potentially signaling an underlying hormonal issue. Diagnostic testing aims to determine if the acne is primary (purely dermatological) or secondary to a systemic condition like Polycystic Ovary Syndrome (PCOS).
Blood work is also mandated before prescribing certain oral medications. Prior to starting the retinoid isotretinoin, baseline blood values are established to ensure the patient can safely begin treatment. This pre-treatment screening ensures the patient’s liver function and lipid profile are within an acceptable range. Baseline tests may also be required before prescribing anti-androgen therapies like spironolactone or certain oral contraceptives.
Specific Diagnostic and Monitoring Panels Used
When a hormonal cause is suspected, dermatologists often order a panel to measure various androgen levels. Key components include total and free testosterone, as elevated levels of these male hormones can lead to increased sebum production and clogged pores. Dehydroepiandrosterone sulfate (DHEA-S) is also measured, as this hormone is produced by the adrenal glands and can indicate a separate source of androgen overproduction.
To screen for conditions like PCOS, the levels of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) are assessed, with a high LH-to-FSH ratio often pointing toward this diagnosis. Other diagnostic tests may include thyroid function tests or inflammatory markers like C-Reactive Protein (CRP) if a broader systemic issue is suspected. These hormonal measurements are typically taken in the first half of the menstrual cycle to ensure the most accurate interpretation.
Monitoring blood work focuses on the body’s reaction to systemic acne medications. For patients taking isotretinoin, regular checks of Liver Function Tests (LFTs) are performed, measuring enzymes like Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST). Elevations in these enzymes can signal liver stress and may necessitate a dosage change. A Lipid Panel, measuring total cholesterol and triglycerides, is also required, as isotretinoin can cause these levels to rise.
Interpreting Results and Treatment Adjustment
Once laboratory results are returned, the dermatologist uses them to confirm a diagnosis or guide the safe continuation of treatment. If the diagnostic panel reveals elevated androgen levels or an abnormal LH-to-FSH ratio, the acne is considered secondary to a condition like PCOS. In this scenario, the dermatologist may introduce targeted hormonal treatments, such as spironolactone, or refer the patient to an endocrinologist for management of the underlying condition.
If the diagnostic workup comes back within normal limits, it confirms the diagnosis of primary acne, meaning the condition is not caused by a systemic hormonal disorder. This result allows the dermatologist to confidently focus treatment on conventional topical or oral therapies.
Conversely, monitoring test results directly dictate medication management, particularly with isotretinoin. If a patient’s ALT or AST levels increase above the baseline or if triglyceride levels become high, the dermatologist will often reduce the medication dosage or temporarily stop the treatment. The patient is then retested to ensure the values return to a safer range before deciding on the next steps.