Armpit Rash

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Published: September 8, 2016
Last reviewed: November 18, 2016

Armpit rash can be caused by shaving (ingrown hair), irritant substances or allergic reaction (contact dermatitis), infection (ringworm, bacterial folliculitis, hidradenitis suppurativa), clogging of the sweat glands (heat rash), overactivity of the sebaceous glands (seborrheic dermatitis) or diseases, such as diabetes or cancer (acanthosis nigricans). Armpit rashes appear on the skin surface, while armpit lumps appear beneath the skin.

Treatment of the armpit rash depends on the cause and it can include topical or oral antibiotics, antifungals, steroids and antihistamines.

Armpit rashes presented below are divided to:

1. Red bumps
2. Scaly patches
3. Dark rashes (hyperpigmentations)
4. Skin tags

1. Red Bumps

1.1. Ingrown Hair

Underarm rash - ingrown hairIngrown hair can develop after waxing, pilling or shaving, especially in people with curly hair. It appears as itchy and tender red bumps with hair arising from them [9].
Prevention and treatment. Avoid shaving close to the skin and unnecessary pilling. The rash can disappear on its own within several weeks [9]. A steroid (hydrocortisone) cream and phototherapy can reduce itching [9].
Picture 1. Ingrown hair (source: Samuel Freire da Silva, M.D., Atlasdermatologico.com.br)

1.2. Bacterial Folliculitis

Underarm rash - staph folliculitisBacterial folliculitis is an infection of the hair follicles, usually by the bacterium Staphylococcus aureus. It appears as multiple itchy or burning red acne-like pimples with white pus-filled centers [1]. It can be caused by friction of tight clothes or frequent shaving.

Treatment is with an ointment containing the antibiotic erythromycin or mupirocin [19].

Picture 2. Bacterial folliculitis (source: Samuel Freire da Silva, M.D., Atlasdermatologico.com.br)

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1.3. Heat Rash

Miliaria - sweat rashHeat rash (sweat rash, prickly heat, miliaria) appears in the form of small translucent itchy or burning blisters, red flat bumps (papules), goose bumps-like rash or deep lumps [7]. It is triggered by sweating. It can heal on its own in several weeks [7].

Treatment is by avoiding sweating and skin irritation, by calamine lotion or steroid creams [16].

Picture 3. Sweat rash or miliaria (source: Samuel Freire da Silva, M.D., Atlasdermatologico.com.br)

1.4. Hidradenitis Suppurativa

Underarm rash - hidradenitis suppurativa Hidradenitis suppurativa (acne inversa) is a chronic inflammation of the hair follicles in the armpits (or under the breasts, in the groin or around the anus) that may develop after puberty, more commonly in obese people. Symptoms include painful red pimples and lumps (abscesses or swollen lymph glands) that may rupture and ooze foul-smelling fluid and eventually scar over [5]. Treatment can include topical or oral antibiotics, retinoids, infliximab and surgical removal of the affected skin [17].

Picture 4. Hidradenitis suppurativa (source: Samuel Freire da Silva, M.D., Atlasdermatologico.com.br)

1.5. Fox-Fordyce Disease

In a rare sweat retention disease or Fox-Fordyce disease, mainly in females between 13 and 35 years of age, blockage of the sweat glands causes red bumps, severe itch and decreased sweating in the armpits, around the nipples and in the pubic area [6]. Treatment can include topical retinoids, steroids and antibiotics [6].

2. Scaly Patches

2.1. Ringworm

Underarm rah - ringwormRingworm is a fungal skin infection caused by Tinea axillaris. It appears as red or brown and scaly patches in the form of circles or rings [3,4]. Risk factors include diabetes mellitus and moist skin.

Treatment: topical or oral antifungals.

Picture 5. Ringworm (source: Samuel Freire da Silva, M.D., Atlasdermatologico.com.br)

2.2. Contact Dermatitis

Underarm rash - contact dermatitisSoaps, deodorants, perfumes, alcohol, topical antibiotics, clothes or dry air can irritate the armpit skin after a single or repeated contact and cause recurring skin inflammation:

  • Irritant contact dermatitis appears as itchy red, dry, scaly or peeling patches with possible cracks (eczema) [10].
  • Allergic contact dermatitis appears as itchy pink blisters or patches (hives or urticaria) [1].

Treatment of irritant contact dermatitis can include moisturizing or steroid creams [10]. Treatment of allergic contact dermatitis can include topical or oral steroids or antihistamines, and tacrolimus or pimecrolimus ointments [11,12].

Picture 6. Contact dermatitis (source: Samuel Freire da Silva, M.D., Atlasdermatologico.com.br)

2.3. Inverse Psoriasis

Underarm rash - psoriasisIn inverse psoriasis, red plaques with silvery scales that may crack and bleed can appear in the armpits, under the breasts and in the groin [1].

Treatment is with steroid ointments, calcipotriene, coal tar or anthralin [25].

Picture 7. Inverse psoriasis (source: Intechopen, Creative Commons licence)

2.4. Erythrasma

Armpit rash - erythrasmaErythrasma is a chronic skin infection caused by the bacteria Corynebacterium. It appears with sharply outlined red or brown scaly patches in the armpits or groin [20]. The rash is rarely itchy [20]. Risk factors include moist environment, diabetes and obesity.

Photodynamic therapy can clear or reduce the rash [21].

Picture 8. Erythrasma (source: Samuel Freire da Silva, M.D., Atlasdermatologico.com.br)

2.5. Seborrheic Dermatitis

Seborrheic dermatitis appears as scaly skin-colored or red patches on the scalp (with dandruff), face, armpits and groin in some people with oily skin. The condition develops due to increased activity of sebaceous glands and associated fungal infection [14]. Treatment can include ointments with salicylic acid, antifungals, steroids, pimecrolimus or tacrolimus [14].

2.6. Hailey-Hailey Disease

Armpit rash - Hailey-Hailey diseaseHailey-Hailey disease or familial benign chronic pemphigus is a hereditary disease with blistering rashes in the skin folds that usually appear in 3rd or 4th decade of life [22].

Treatment can include topical steroids, antibiotics and benzoyl peroxide [22].

Picture 9. Hailey-Hailey disease (source: Wikipedia, Creative Commons licence)

2.7. Intertrigo

Intertrigo is a general term for inflamed skin in the body folds, such as under the arms and breasts or in the groin [1,2]. It appears as itchy or burning red or brown patches that are moist and can peel off [1,2]. Risk factors include genetic predisposition, obesity and hyperhidrosis [13].

3. Dark Rashes (Hyperpigmentations)

3.1. Acanthosis Nigricans


Armpit rash - acanthosis nigraAcanthosis nigricans
refers to thick dark skin that appears on the back of the neck, in the armpits and groin in certain conditions, such as obesity, diabetes mellitus, stomach or other cancer, or as a side effect of drugs (nicotinic acid, insulin, corticosteroids, hormones) [8]. The rash is rarely itchy and can disappear after treatment of the underlying condition.

Treatment of the rash itself may not be very effective, but can include triple-combination depigmenting cream (tretinoin, hydroquinone, fluocinolone acetonide) or oral drugs, such as etretinate and isotretinoin [15].

Picture 10. Acanthosis nigricans (source: Dr. Fedro Portugal, Atlasdermatologico.com.br)

 

 

4. Skin Tags

Skin tagsA skin tag (acrochordon) is a piece of skin in the form of “stalk” or “berry” that freely hangs down. Skin tags can be skin-colored or dark brown and are usually painless and harmless. A doctor can tell if there is any danger of development into a cancer.

Picture 11. Skin tags (source: Wikipedia, Creative Commons licence)

 

 

 

Prevention and Home Remedies

  • Wear loose airy clothes, heat and excessive alcohol drinking to avoid moist in armpits.
  • Avoid deodorants, antiperspirants and armpit shaving.
  • Do not scratch, if possible, at least not with the nails.
  • To reduce itch–only when the skin is not cracked–you can apply [24]:
    • Moist cold dressing (for eczema)
    • Moist warm dressing (for ingrown hair, folliculitis)
    • Baking soda paste
    • Calamine lotion (for hives, not for dry skin) [23]
    • Colloidal oatmeal (for eczema)
    • Menthol/camphor lotion
    • Moisturizing creams or emollients (for dry skim eczema)

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