Differential Diagnosis for Red Itchy Painful Rash in Armpit
Single Most Likely Diagnosis
- Intertrigo: This is the most common diagnosis for a red, itchy, and painful rash in the armpit. Intertrigo is a type of skin inflammation caused by friction, moisture, and bacterial or fungal overgrowth in skin folds, making the armpit a prime location. It's characterized by redness, itching, and sometimes a foul odor.
Other Likely Diagnoses
- Contact Dermatitis: This could be due to an allergic reaction or irritant exposure from deodorants, antiperspirants, or other personal care products. Symptoms include redness, itching, and small blisters.
- Eczema (Atopic Dermatitis): Eczema can occur in the armpits and is characterized by itchy, inflamed skin that can become red and painful.
- Folliculitis: An infection of the hair follicles, often caused by bacteria like Staphylococcus aureus. It presents with red, itchy, and painful bumps or pus-filled bumps in the affected area.
- Candidiasis: A fungal infection that thrives in warm, moist areas like the armpits. It causes a red, itchy, and sometimes painful rash.
Do Not Miss Diagnoses
- Cellulitis: A bacterial skin infection that can spread rapidly and become serious. While less common in the armpit, it's crucial to identify due to its potential severity. Symptoms include redness, swelling, warmth, and pain.
- Abscess: A collection of pus that has built up within the tissue of the body, indicating a severe infection. An abscess in the armpit can cause pain, swelling, and redness.
- Lymphoma: Although rare, cutaneous T-cell lymphoma (like mycosis fungoides) can initially present with skin symptoms that might resemble a rash, including in the armpits.
Rare Diagnoses
- Inverse Psoriasis: A type of psoriasis that occurs in skin folds, such as the armpits. It's less common than other forms of psoriasis and presents with smooth, red, and sometimes itchy patches.
- Keratolysis Exfoliativa (Lamellar Dyskeratosis): A rare condition characterized by recurrent episodes of peeling of the skin, often starting in the armpits or groin.
- Granuloma Gluteale Infantum: Though more common in the diaper area of infants, it can occasionally occur in other skin folds like the armpits, presenting with reddish-brown nodules.