Differential Diagnosis for 16-year-old Female with Underarm Irritation
- Single most likely diagnosis:
- Contact dermatitis: This is the most likely diagnosis given the patient's history of using antiperspirant or deodorant (implied by "air under her arms") and subsequent development of irritation and discoloration in the underarm area. The symptoms of itchiness and discoloration are consistent with an allergic or irritant reaction to a substance.
- Other Likely diagnoses:
- Eczema (atopic dermatitis): This condition can cause itchy, inflamed skin and may be exacerbated by irritants such as antiperspirants or deodorants.
- Folliculitis: An infection of the hair follicles, which can cause redness, itching, and inflammation, particularly in areas with high apocrine gland concentration like the underarms.
- Hyperpigmentation (post-inflammatory): This could be a result of the initial irritation, leading to discoloration.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Hidden malignancy (e.g., apocrine gland carcinoma): Although extremely rare, any persistent or unexplained skin lesion or irritation should prompt consideration of malignancy.
- Infectious diseases (e.g., tuberculosis, fungal infections): Certain infectious diseases can cause skin lesions and should be considered, especially if the patient has been exposed to someone with a similar condition or has recently traveled.
- Rare diagnoses:
- Fox-Fordyce disease: A rare condition characterized by itchy, follicular papules in the apocrine-gland-bearing areas, such as the underarms.
- Hailey-Hailey disease (familial benign chronic pemphigus): An inherited blistering skin condition that can affect the underarms and groin areas, although it typically starts at a younger age.
- Granulosis rubra nasi: A rare condition that can cause redness, sweating, and follicular papules, typically on the nose but can occasionally affect other areas.