Redness and pain in the armpit

Axillary pain and redness may result from skin symptoms caused by regrowth of underarm hair after shaving, which is a normal physiological phenomenon. On the other hand, conditions such as herpes zoster, folliculitis, or infected sebaceous cysts can also trigger symptoms of axillary pain and redness. It is generally recommended to promptly visit a hospital for necessary examinations and early treatment to prevent disease progression and prolonged illness.

I. Non-disease Factors

Axillary pain and redness may occur due to regrowth of underarm hair following hair removal, leading to skin irritation. This is considered a normal physiological response that typically does not require specific treatment and usually resolves on its own within a short period. There is no need for excessive concern.

II. Disease-related Factors

1. Herpes Zoster

Axillary pain and redness could also be an early sign of herpes zoster (shingles), an acute infectious skin condition caused by the varicella-zoster virus. Early and adequate antiviral therapy is crucial to reduce neuralgia, shorten the disease course, and alleviate symptoms. Commonly used medications include acyclovir, valacyclovir, famciclovir, or brivudine. These drugs are generally safe but should be used under medical supervision, as they may rarely cause adverse reactions such as phlebitis, rash, nausea, or vomiting. Local treatments such as semiconductor laser or infrared irradiation may also be applied to promote nerve repair, facilitate drying and crusting of blisters, and relieve pain.

2. Folliculitis

Folliculitis is an infection of the hair follicles and sebaceous glands caused by pyogenic bacteria such as *Staphylococcus aureus* or *Staphylococcus epidermidis*. It can occur in any area with hair follicles, and the armpit is one of the common sites. In the early stage, it appears as small red papules around the follicular openings, which gradually develop into small pustules, often with a hair passing through the center. For bacterial infections, topical antibiotics such as mupirocin ointment, fusidic acid cream, compound polymyxin B ointment, or clindamycin gel may be used as directed by a physician. For fungal infections, antifungal agents such as ketoconazole cream or shampoo, econazole cream, or terbinafine cream may be prescribed. If the condition worsens and lesions progress to furuncles or carbuncles, the doctor may perform incision and drainage under sterile and disinfected conditions to remove pus. Patients with folliculitis may also benefit from physical therapies such as ultrashort wave, far-infrared irradiation, or photodynamic therapy, which have anti-inflammatory, analgesic, and anti-infective effects.

3. Sebaceous Cyst

Sebaceous cysts are mostly caused by blockage of the opening of hair follicles and sebaceous glands. Small cysts usually do not cause noticeable discomfort, but larger ones may compress surrounding tissues and lead to symptoms. When occurring on the face, they may also affect appearance. Surgical removal is a common treatment option for sebaceous cysts. Postoperative wound care is essential to ensure proper healing.

In addition to the above conditions, axillary pain and redness may also be caused by intertrigo, axillary eczema, hidradenitis suppurativa, or lymphadenitis. Axillary pain and redness should be taken seriously. Prompt medical evaluation and timely treatment are important. During treatment, maintaining skin cleanliness and hygiene is essential to prevent secondary infection.