Differential Diagnosis for 69-year-old Caucasian Female

Single Most Likely Diagnosis

• Factitial Dermatitis with Underlying Psychiatric Condition: The presence of factitial dermatitis, severe anxiety, and severe depression suggests a psychiatric condition such as dermatitis artefacta, where the patient intentionally creates skin lesions. The absence of systemic symptoms like stomach issues and the specific nature of the skin lesions support this diagnosis.

Other Likely Diagnoses

• Delusional Parasitosis: This condition involves a fixed delusion that one is infested with parasites, leading to self-inflicted skin lesions. The patient's severe anxiety and depression could contribute to or result from this delusional state.
• Psychogenic Excavation Disorder: Similar to factitial dermatitis, this involves the intentional creation of skin lesions, often associated with underlying psychiatric issues.
• Neurotic Excoriations: This condition is characterized by the repetitive scratching of the skin, often in response to stress or anxiety, leading to lesions similar to those described.

Do Not Miss Diagnoses

• Cutaneous Malignancy: Although less likely given the description of the lesions, it's crucial to rule out skin cancers such as basal cell carcinoma or squamous cell carcinoma, especially in a 69-year-old patient.
• Infectious Diseases (e.g., Cellulitis, Impetigo): Despite the absence of drainage, odor, or edema, infectious causes should be considered, especially if the patient's immune status is compromised.
• Autoimmune Disorders (e.g., Discoid Lupus Erythematosus): These conditions can present with skin lesions and are associated with various systemic symptoms, including psychiatric manifestations.

Rare Diagnoses

• Erythema Dyschromicum Perstans: A rare condition characterized by the gradual appearance of hyperpigmented and hypopigmented macules, which could be considered if the lesions do not respond to typical treatments for factitial dermatitis.
• Morgellons Disease: A controversial condition characterized by the presence of skin lesions and the sensation of crawling under the skin, often associated with psychiatric symptoms. However, its recognition and diagnosis are not universally accepted in the medical community.