Overview

Underarm rash refers to irritation, redness, or inflammation that develops in the armpit area. Due to the warm, moist, and often enclosed environment of the underarms, this area is particularly susceptible to rashes caused by friction, infections, allergic reactions, or heat. Underarm rashes can range from mild discomfort to severe itching, pain, and skin breakdown. While many cases are harmless and resolve with simple care, persistent or worsening rashes may indicate underlying skin conditions requiring medical attention.

Causes

Several factors can contribute to the development of an underarm rash, including:

• Friction (Chafing): Repeated rubbing of skin against skin or clothing can cause irritation and rash, especially during exercise or in hot weather.
• Heat Rash (Miliaria): Blocked sweat glands lead to trapped sweat under the skin, causing red bumps and irritation, commonly in hot and humid conditions.
• Contact Dermatitis: Allergic reactions to deodorants, antiperspirants, soaps, or laundry detergents can trigger an itchy rash.
• Fungal Infections: Yeast infections, particularly caused by Candida species, thrive in moist areas like the underarms, causing red, itchy, and sometimes scaly rashes.
• Bacterial Infections: Conditions like erythrasma caused by Corynebacterium can cause reddish-brown patches in the armpits.
• Intertrigo: Inflammation from skin-to-skin friction worsened by sweat, leading to red, raw, and painful skin.
• Psoriasis: Chronic autoimmune condition that can cause smooth, red patches in the underarm area (inverse psoriasis).
• Eczema (Atopic Dermatitis): Causes dry, itchy, and inflamed skin, including in the armpits.
• Shaving Irritation: Razor burns, ingrown hairs, and minor cuts from shaving can cause localized rash and bumps.

Symptoms

The symptoms of an underarm rash can vary depending on the cause but commonly include:

• Redness: Pink or red discoloration of the underarm skin.
• Itching: Persistent or severe itchiness is a hallmark of many underarm rashes.
• Burning Sensation: Stinging or burning pain, especially with friction or sweating.
• Swelling: Mild to moderate swelling or puffiness in the affected area.
• Blisters or Bumps: Small raised spots, blisters, or pustules may develop in certain types of rashes.
• Peeling or Flaking: Dry, peeling, or cracked skin may follow initial irritation.
• Odor: Fungal or bacterial infections can cause a noticeable unpleasant smell.
• Discomfort with Movement: Activities like raising arms or exercising may worsen pain or itching.

Diagnosis

Diagnosing the cause of an underarm rash involves a clinical assessment by a healthcare provider, sometimes supplemented by additional tests:

• Medical History: Discussion of recent activities, product use (e.g., deodorants), hygiene habits, and any underlying health conditions.
• Physical Examination: Visual inspection of the rash’s appearance, distribution, and severity.
• Skin Swab or Culture: Swabbing the affected area to test for fungal or bacterial infections if infection is suspected.
• Patch Testing: Used to identify contact allergies when allergic dermatitis is a concern.
• Wood’s Lamp Examination: A special light that helps detect certain bacterial or fungal infections like erythrasma.

Treatment

Treatment depends on the underlying cause of the underarm rash and may include:

Home Remedies

• Keep the Area Dry and Cool: Reducing moisture helps resolve minor rashes.
• Avoid Irritants: Discontinue deodorants, soaps, or fabrics that may be causing irritation.
• Cold Compresses: Applying cool packs can soothe burning and itching sensations.

Medications

• Antifungal Creams: Used for treating yeast or fungal infections (e.g., clotrimazole, miconazole).
• Topical Steroids: Low to medium potency steroids (e.g., hydrocortisone) to reduce inflammation and itching.
• Antibiotic Creams or Oral Antibiotics: For bacterial infections such as erythrasma.
• Antihistamines: Oral or topical medications to relieve allergic itchiness.

Medical Procedures

• Laser Therapy: Occasionally used for chronic bacterial conditions like hidradenitis suppurativa.
• Drainage: For abscess formation under the arm, minor surgical procedures may be necessary.

Prognosis

In most cases, underarm rashes respond well to treatment and improve within a few days to weeks. Fungal and bacterial infections typically resolve completely with appropriate medications, while allergic or irritant reactions improve once the triggering substance is removed. Chronic skin conditions like eczema or psoriasis may require long-term management but can be controlled effectively with proper care.

To prevent recurrence, it is important to maintain good hygiene, avoid known irritants, keep the underarm area dry, and use gentle skin care products. Early treatment can help avoid complications such as secondary infections, scarring, or persistent skin irritation.