Contact Dermatitis: This is a common condition that can cause a hyperpigmented dry peri oral rash due to an allergic reaction or irritation from substances like cosmetics, toothpaste, or food. The rash typically appears after exposure to the offending agent and can be accompanied by itching and dryness.

Atopic Dermatitis (Eczema): Characterized by dry, itchy, and inflamed skin, atopic dermatitis can lead to hyperpigmentation, especially in individuals with darker skin tones. The peri oral area can be involved, especially if there's a history of atopic dermatitis.
Seborrheic Dermatitis: This condition causes scaly patches, red skin, and stubborn dandruff due to an oily scalp. It can also affect the face, including the peri oral area, leading to a hyperpigmented rash.
Peri Oral Dermatitis: A condition that specifically affects the skin around the mouth, characterized by a rash, redness, and sometimes papules or pustules. It can be caused by various factors, including cosmetics, hormonal changes, or bacterial overgrowth.

Lupus: Systemic lupus erythematosus (SLE) can cause a butterfly-shaped rash across the cheeks and nose, which might extend to the peri oral area. Although less common, missing lupus could have significant implications due to its systemic nature.
Sarcoidosis: This condition can cause skin lesions, including rashes around the mouth, along with systemic symptoms like fever, weight loss, and joint pain. Early diagnosis is crucial due to its potential to affect multiple organ systems.

Melasma: Although more common on the face, particularly on the cheeks and forehead, melasma can occasionally appear around the mouth, causing hyperpigmentation. It's more common in women, especially during pregnancy or with hormonal changes.
Fixed Drug Eruption: A rare condition where certain medications cause a skin reaction, leading to hyperpigmented lesions. The peri oral area can be involved, and the reaction typically recurs at the same site upon re-exposure to the offending drug.