Testosterone replacement therapy (TRT) effectively treats clinically confirmed hypogonadism, but skin reactions represent one of the most common side effects reported by patients. These reactions can occur with any administration route—gels, injections, or patches—and range from mild localised irritation to more troublesome rashes requiring medical intervention. Understanding how to identify, manage, and prevent testosterone-related skin reactions is essential for maintaining treatment adherence whilst minimising discomfort. Most reactions are manageable without discontinuing therapy, provided you recognise the type of rash and implement appropriate treatment strategies. This guide explains evidence-based approaches to treating testosterone-induced rashes, when to seek medical advice, and how to prevent future reactions.

Understanding Skin Reactions to Testosterone Treatment

Testosterone replacement therapy (TRT) is prescribed for men with clinically confirmed hypogonadism, where the body produces insufficient testosterone. Whilst this treatment can significantly improve symptoms such as fatigue, reduced libido, and mood disturbances, skin reactions represent one of the more common adverse effects reported by patients.

Skin reactions to testosterone treatment can occur regardless of the administration route, though they manifest differently depending on whether the therapy is delivered via gels, intramuscular injections, or less commonly in the UK, transdermal patches or subcutaneous implants. Transdermal preparations are particularly associated with localised skin reactions, with application-site reactions being common with patches. The mechanisms underlying these reactions are multifactorial and may include:

• Contact dermatitis from excipients in gels or adhesive components in patches

• Irritant reactions to the alcohol base in topical formulations

• Folliculitis or acne resulting from increased sebum production

• Allergic hypersensitivity to pharmaceutical additives (rarely to testosterone itself)

It is important to distinguish between expected pharmacological effects—such as mild acne due to increased sebaceous gland activity—and true adverse reactions requiring intervention. The former represents a normal physiological response to androgen stimulation, whilst the latter may necessitate treatment modification. Understanding the nature of your skin reaction is the first step towards effective management and ensuring that testosterone therapy remains both tolerable and beneficial. Most skin reactions are manageable without discontinuing treatment, though this requires proper identification and appropriate intervention.

Identifying Different Types of Testosterone-Related Rashes

Accurate identification of the type of rash you are experiencing is essential for determining the most appropriate management strategy. Different testosterone formulations and individual patient factors can produce distinct cutaneous manifestations.

Contact dermatitis is the most frequently encountered reaction with transdermal preparations. This typically presents as erythema (redness), itching, and sometimes vesicle formation confined to the application site. The rash usually appears within hours to days of application and may worsen with repeated exposure. With patches, you may notice a clear outline corresponding to the patch shape, whilst gel applications may produce more diffuse reactions.

Acne and folliculitis represent androgenic effects rather than true allergic reactions. These manifest as pustules, papules, or comedones, commonly affecting the face, chest, and back—areas with high sebaceous gland density. This occurs because testosterone increases sebum production and can alter the follicular environment, promoting bacterial colonisation with Cutibacterium acnes (formerly Propionibacterium acnes).

Injection site reactions from intramuscular testosterone may include pain, swelling, erythema, or occasionally sterile abscesses. These typically resolve within days but can be uncomfortable. Subcutaneous implants, which are uncommon in the UK, may cause localised inflammation, bruising, or rarely, extrusion reactions.

Generalised allergic reactions are uncommon but may present as widespread urticaria (hives), pruritus without visible rash, or in rare cases, more serious manifestations. If you develop facial swelling, difficulty breathing, or widespread rash, call 999 or go to A&E immediately as these symptoms may indicate anaphylaxis, a medical emergency.

Documenting the timing, location, and characteristics of your rash—ideally with photographs—can assist your healthcare provider in making an accurate diagnosis and recommending targeted treatment.

Immediate Steps to Manage a Testosterone Treatment Rash

When you first notice a rash related to testosterone treatment, several immediate measures can provide relief and prevent worsening whilst you arrange medical review.

For localised reactions to transdermal preparations:

• Rotate application sites systematically if using gels. For patches, follow product-specific guidance which typically recommends waiting at least seven days before reapplying to the same area

• Cleanse the area gently with lukewarm water and a mild, fragrance-free cleanser. Avoid hot water, which can exacerbate inflammation

• Apply a cool compress for 10-15 minutes several times daily to reduce inflammation and itching

• Avoid scratching, as this can introduce secondary bacterial infection and worsen dermatitis

General measures applicable to all rash types:

• Moisturise regularly with SLS-free emollients. These help restore the skin barrier and reduce irritation. Apply liberally and frequently, particularly after washing

• Wear loose, breathable clothing made from natural fibres like cotton to minimise friction and allow air circulation

• Avoid potential irritants including perfumed products, harsh soaps, and fabric softeners that may compound the reaction

For gel applications, always wash your hands thoroughly after applying, allow the gel to dry completely (typically 3-5 minutes) before dressing, and cover the application site with clothing to prevent transfer to others. Avoid washing or swimming for at least 2 hours after application (check your specific product's guidance for exact timings).

For injection site reactions, applying a cold pack immediately after injection may reduce inflammation. Do not massage the injection site as this is not recommended for testosterone injections.

Do not discontinue testosterone therapy without consulting your prescribing clinician, as abrupt cessation can cause symptom recurrence. However, if you experience severe reactions—such as extensive blistering, signs of infection (increasing pain, warmth, purulent discharge), or systemic symptoms—seek prompt medical advice. These immediate measures are intended as first-line management whilst you arrange appropriate medical review for definitive treatment.

Medical Treatments for Testosterone-Induced Skin Reactions

When self-care measures prove insufficient, several medical treatments can effectively manage testosterone-related skin reactions. Your GP or endocrinologist will tailor treatment based on the type and severity of your rash.

For contact dermatitis and localised inflammation:

Topical corticosteroids represent first-line pharmacological treatment. Mild-to-moderate potency preparations such as hydrocortisone 1% or clobetasone butyrate 0.05% are typically prescribed for facial or genital areas, whilst more potent formulations like betamethasone valerate 0.1% may be used on the trunk or limbs. These should be applied thinly once or twice daily for a limited duration (typically 7-14 days) to avoid skin atrophy. The British Association of Dermatologists recommends using the lowest effective potency for the shortest duration necessary.

Oral antihistamines such as cetirizine 10mg or loratadine 10mg once daily can reduce pruritus significantly, improving comfort and sleep quality. Topical antihistamines are not recommended due to the risk of skin sensitisation.

For acne and folliculitis:

Following NICE guidance (NG198), first-line treatment typically involves combination topical therapy with benzoyl peroxide and either a topical retinoid (adapalene, tretinoin) or topical antibiotic. These help normalise follicular keratinisation and reduce bacterial colonisation. For moderate-to-severe cases, oral antibiotics such as lymecycline 408mg once daily or doxycycline 100mg once daily may be prescribed for up to 12 weeks, but should be used in combination with topical benzoyl peroxide to reduce antibiotic resistance. Severe cases may require dermatology referral.

Formulation modification often proves highly effective. Your clinician may:

• Switch between different gel formulations with alternative excipients

• Transition to intramuscular injections if transdermal routes prove intolerable

• Adjust dosing frequency or application technique

For persistent or severe reactions, referral to dermatology may be warranted for patch testing to identify specific allergens, or consideration of alternative testosterone formulations. In selected cases where all topical routes cause reactions, long-acting intramuscular preparations (testosterone undecanoate) administered every 10-14 weeks by a healthcare professional may provide an effective alternative with minimal cutaneous involvement.

When to Seek Medical Advice About Your Rash

Whilst many testosterone-related skin reactions are mild and manageable with self-care, certain features warrant prompt medical evaluation to prevent complications and ensure treatment safety.

Call 999 or go to A&E immediately if you experience:

• Facial or tongue swelling, difficulty breathing, dizziness, or widespread urticaria (hives), which may indicate anaphylaxis—a medical emergency requiring immediate treatment

Seek urgent medical attention (same-day GP appointment or NHS 111) if you experience:

• Signs of infection: increasing pain, warmth, swelling, purulent discharge, red streaking from the rash site, or fever above 38°C. These may indicate bacterial superinfection requiring antibiotic therapy

• Severe or spreading rash: extensive blistering, skin breakdown, or rapidly expanding erythema beyond the application site

• Severe pain at injection sites that worsens rather than improves, particularly if accompanied by swelling or inability to bear weight

Arrange a routine GP appointment (within 1-2 weeks) if:

• Mild-to-moderate rash persists beyond two weeks despite self-care measures

• The rash significantly impacts your quality of life or causes sleep disturbance

• You develop acne that does not respond to over-the-counter treatments

• You experience recurrent reactions despite rotating application sites

• You are uncertain about the nature of your rash or appropriate management

Contact your prescribing clinician if you are considering discontinuing testosterone therapy due to skin reactions. They can explore alternative formulations or adjunctive treatments that may allow continuation of necessary hormone replacement. Abrupt cessation without medical guidance may result in recurrence of hypogonadal symptoms and is not recommended.

For patients under specialist endocrinology care, your consultant's secretary can often provide advice between appointments. Many NHS trusts also offer advice lines for patients on hormone replacement therapy. Documentation is valuable—photographs of the rash, noting timing relative to testosterone administration, can significantly assist clinical assessment, particularly if the rash has resolved by the time of your appointment.

If you suspect your rash is a side effect of testosterone treatment, you can report it through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk).

Preventing Future Skin Reactions During Testosterone Therapy

Proactive strategies can significantly reduce the likelihood and severity of skin reactions, enabling you to continue testosterone therapy with minimal disruption.

Optimising application technique for transdermal preparations:

• Systematic site rotation is paramount. Maintain a written schedule or use a smartphone app to track application sites, ensuring you vary the application area according to your product's guidance

• Prepare the skin properly: ensure the area is clean, completely dry, and free from cuts, irritation, or recent shaving before application

• Apply to recommended sites only: typically the shoulders, upper arms, or abdomen for gels; follow product-specific guidance. Avoid areas with thin skin or high friction

• Allow adequate drying time for gels (typically 3-5 minutes) before dressing to prevent transfer and reduce local irritation

• Always wash hands thoroughly after applying gel to prevent accidental transfer to others

• Avoid swimming or bathing for at least 2 hours after gel application (check your specific product's guidance for exact timings)

• Cover the application site with clothing once dry to prevent transfer to others, particularly women and children

Skin care regimen:

Establish a consistent routine using SLS-free emollients liberally and frequently—ideally 3-4 times daily. This maintains skin barrier function and reduces susceptibility to irritation. Choose fragrance-free, hypoallergenic products. Apply emollients after washing and at times separate from testosterone application.

For injection-based therapy:

• Note that testosterone undecanoate (Nebido) injections should be administered by a healthcare professional

• For other injectable formulations, ensure proper injection technique if you've been trained to self-administer

• Follow healthcare professional guidance on injection sites and technique

Lifestyle modifications:

• Maintain good hygiene without over-washing, which can strip natural skin oils

• Wear breathable, loose-fitting clothing

• Manage stress, which can exacerbate inflammatory skin conditions

• Avoid known personal triggers for skin sensitivity

Regular monitoring: Attend scheduled follow-up appointments where testosterone levels and treatment tolerability are assessed. Early discussion of minor skin changes allows intervention before reactions become problematic. By implementing these preventive strategies consistently, most patients can continue testosterone therapy long-term with minimal cutaneous adverse effects.

Frequently Asked Questions