Rash Under Armpit: Causes and Treatments

Having a disfiguring , itchy, painful rash under the armpit is a very stressful situation for anyone regardless of their age or gender. Of course there are lot of causes for these kind of rashes in the armpits.

Knowing what causes rashes under the armpit, the symptoms that differentiate one from another, how to mange such rashes, and when to seek dermatological consultation will be helpful for knowledge seeking adults and teenagers to address their problem in a more scientific way.

Rash under the arm with itchy red skin and small bumps, commonly associated with intertrigo.

Why do we get rashes under the armpit area?

The armpit area, also called the axilla, contains apocrine sweat glands. They produce odourless sweat in response to heat and psychological stimuli. The odour develops after skin bacteria break it down. The armpit area is flexural and can retain moisture, which isn’t easily removed. Additionally, the armpit area is exposed to cosmetic substances and different fabrics in clothing. These factors tend to precipitate rashes around the axillary area more often.^[1]

Common causes of armpit rashes

Chafing

Symptoms: Burning sensation over the rubbed area, swelling, redness, and crusting. Can lead to blistering.

Causes: When skin in a part of your body continuously rubs against each other or a fabric, it leads to chafing.

Treatment: Wear moisture-wicking, loose-fitting clothes during physical activity. Avoid clothes made of cotton, as cotton soaks up sweat and moisture, which can lead to friction and chafing. Apply powder or petroleum jelly to affected areas.^[2]

Heat rash (miliaria)

Symptoms: Development of multitudes of uniformly spaced vesicles without underlying redness, often occurring after a fever or heavy exertion. The vesicles look like droplets of water lying on the surface, but the skin is dry to the touch. Can present as tiny, prickly, red, slightly raised itchy bumps.

Causes: Result of plugging or rupture of sweat ducts. It occurs in hot humid climates, at any age, and is common in over-clothed infants in hot nurseries.

Treatment: Self-limiting and usually requires no treatment.^[3] Move to a cooler environment, keep the skin dry, wear loose clothing, use cool compresses will be helpful in prevention.

Contact dermatitis – allergic and irritant

Symptoms: Itchy skin, rash, excessively dry skin, tender skin, burning or stinging, hives, fluid-filled blisters, oozing blisters that leave crusts and scales.

Causes: When your skin becomes irritated due to an external stimulus ( deodorants, soaps, laundry detergents, or fabrics) or allergen and avoidance of the exposure clears the eruption, it is likely due to contact dermatitis. Irritants cause keratinocyte damage without mounting an immunological memory, while allergic contact dermatitis involves a type IV hypersensitivity reaction.

Treatment:

Irritant contact dermatitis – Avoidance of irritants responsible for the condition, protective clothing

Allergen contact dermatitis – Topical corticosteroids, avoidance of the relevant allergen.^[3]

Atopic dermatitis

Symptoms: Chronically itchy skin, history of itchiness in skin creases : such as folds of the elbows, behind the knees, fronts of ankles or around the neck  history of asthma or hay fever, general dry skin, visible flexural eczema, onset in the first 2 years of life.

Causes: Due to overproduction of IgE antibodies for environmental allergens in susceptible individuals.

Treatment: Avoidance of the allergen, use of emollients, topical steroids, and calcineurin inhibitors, phototherapy and immunosuppressants will be helpful.^[3]

Seborrheic dermatitis

Symptoms: Pain, tenderness, itchiness, burning sensation.

Causes: Causes a scaly rash commonly appearing in oily areas like the forehead and scalp. Maceration( skin break down) can occur in areas like the armpits.

Treatment: Proper skin care. Use of dermatologist-recommended moisturizers, shampoos, cleansers, and personal care products.^[4]

Candidasis

Symptoms: A moist, glazed area of erythema and maceration appears in a body fold; the edge shows soggy scaling and outlying satellite papules.

Causes: In extensive cases due to suppression of the immune system due to systemic antibiotic therapy, immunosuppressive drug use, diseases like diabetes or HIV. The causative agent is Candida albicans : a fungi naturally lives in your skin

Treatment: Topical and systemic antifungals. Keep the area dry and clean. Treating the cause of immunosuppression is very important.^[3]

Folliculitis

Symptoms: Can occur anywhere on the skin except palms and soles. Can be asymptomatic, itchy, or painful.

Causes: Infection in hair follicles, often by bacteria like Staph aureus. Damage to the hair follicles by frequent touching, tight clothing, skin rub against skin, or shaving.

Treatment: Warm compresses, avoiding shaving, waxing or plucking the area at least for 1 month, and seeking dermatological advice if not resolved.^[3]

Flexural Psoriasis

Symptoms: Glistening, sharply demarcated red plaques, not scaly.

Causes: Vicious cycle of keratinocyte proliferation and inflammatory reaction producing plaque like lesions. This has a genetic inheritance whilst trauma, infections, hormonal changes, sunlight, some medications, cigarette smoking, and emotions trigger it. Flexural psoriasis affects women and elderly people. More common in HIV infected patients

Treatment: supportive treatment is available. They include topical, ultraviolet radiation, systemic and biological. Treatment choice based on the severity.^[3]

Hidradenitis suppurativa

Symptoms: Papules, pustules, comedones, cysts, sinuses, and scars in axillae, groin, and perianal area. Can be painful, messy, unsightly, and smelly too.

Causes: Chronic suppurative ( pus forming) disorder of the apocrine sweat glands The cause is unknown but an underlying follicular abnormality seems likely. Genetics also play a role in one third of patients. Mixture of aerobic and anaerobic bacteria are frequently found .

Treatment: Risk reduction – includes weight loss, smoking cessation. Systemic antibiotics, anti inflammatory drugs, If it is ineffective draining the chronic pus collection.^[3]

Intertrigo

Intertrigo presenting as a rash under the armpit, featuring itchy red skin and small bumps, commonly found in body fold areas.

Symptoms: usually Chronic with insidious onset of itching, burning, pain, and stinging in skin folds. Initial mild erythematous patch may progress to weeping, erosions, fissures, maceration, or crusting.

Causes: Inflammatory condition of skin folds, worsened by heat, moisture, maceration, friction, and lack of air circulation. induced or aggravated by heat, moisture, maceration, friction, and lack of air circulation.

Intertrigo frequently is worsened by infection, which most commonly is with Candida species. Bacterial, viral, or other fungal infection may also occur.

Treatment: Drying agents, antimicrobial agents, and steroids.^[6]

Ringworm (Tinea corporis)

Symptoms: characterized by plaques with scaling and erythema , most pronounced at the periphery. Lesions expand slowly and healing in centre leaves a typical ring like pattern

Causes: caused by three genera of dermatophyte fungi. They invade keratin only, and fungal metabolic products mount a delayed type hypersensitivity reaction.

Treatment: for minor infections local application of  imidazole preparation, whit- field’s ointment and tolnaftate. In non responsive severe infections systemic antifungal treatment is indicated.^[3] Keep the area dry and clean.

Acanthosis nigricans

Symptoms: Dark velvety thickening and pigmentation of the major flexures.

Causes: Obesity, metabolic syndrome including type 2 diabetes with insulin resistance or by drugs such as nicotinic acid used to treat hyperlipidaemia, malignant tumour in the body.

Treatment: successful management of underlying cause, topical treatments for the skin.^[3]

Erythrasma

Symptoms: Symptom free macular wrinkled, slightly scaly, pink, brown or macerated white areas.

Causes: overgrowth of some diptheroid members of the skin flora produce porphyrins. They tend to grow in a suitable medium

Treatment: Topical fusidic acid or azoles will clear the condition.^[3]

Secondary Syphilis

Symptoms: symmetrically distributed coppery ham coloured lesions. not usually itchy or painful. This will associated with systemic features and lymph node enlargement.

Causes: Sexually transmitted infection with the causative organism, treponema palidum, may be congenital or acquired. Primary syphilis manifest as a painless ulcer ( chancres) in the area of inoculation. Following 4 to 12 weeks of the inoculation patients develop the secondary syphilis.

Treatment: antibiotics.^[3]

Cancer related rashes

Several skin cancers can present as a armpit rashes. About 3% of patients with internal cancer have cutaneous spread. Indicates poor prognosis, but sometimes solitary skin lesion may be the first ever sign of a cancer!

Symptoms: Primary skin cancers may exhibit – ABCDE stands for asymmetry, border, color, diameter and evolving abnormalities.metastasis will appear sharply demarcated and firm area of erythema-carcinoma erysipeloides, firm telangiectatic plaques and papules – carcinoma telangiectoides, skin like orange peel – peau d’orange

Causes: metastasis from breast, lung, gastrointestinal tract, prostate and kidney.

Treatment: Treatment of the primary tumour and Excision of localized lesions.^[3]

Complications of armpit rash

If armpit rash left untreated they can develop into scars, secondary infections and ultimately reducing the quality of life. Some infections have a tendency to transmit to others trough inoculation. Since some rashes may be a sign of systemic illness like diabetes , cancers neglecting them would worsen the prognosis of the systemic condition.

When to see a doctor

If your lesions are new, rapidly growing, or not resolving with self-care, it is important to see a doctor for proper medical advice to prevent complications.

In summary

Armpit rashes can originate from inflammatory, infective causes, or systemic illnesses. Identifying the cause helps in planning treatment and its success. Taking good care of the armpits, a susceptible area for developing rashes, and seeking medical advice early will improve outcomes.

Some armpit rashes are part of the eczema family, such as atopic and contact dermatitis. See our full eczema overview to understand the different types.