A 65-year-old woman comes to the physician with a 5-day history of rash and generalized itching. She initially developed a rash on her hand that spread to her feet, abdomen, and groin area. The patient also has intense pruritus that is worse at night. Her husband started having similar symptoms approximately 3 days ago. She works as a patient aide in a nursing home and has no other medical conditions. The patient had chickenpox when she was 7 years old. Her vital signs are within normal limits. Skin examination (image below) shows multiple small erythematous papules on her palms, sides of the fingers, wrists, lateral aspect of the feet, and periumbilical area. Her husband has similar lesions on the same body parts and also over the shaft of his penis. The remainder of her examination is within normal limits.
Which of the following is the best next step in management of this patient?

Question

A 65-year-old woman comes to the physician with a 5-day history of rash and generalized itching.  She initially developed a rash on her hand that spread to her feet, abdomen, and groin area.  The patient also has intense pruritus that is worse at night.  Her husband started having similar symptoms approximately 3 days ago.  She works as a patient aide in a nursing home and has no other medical conditions.  The patient had chickenpox when she was 7 years old.  Her vital signs are within normal limits.  Skin examination (image below) shows multiple small erythematous papules on her palms, sides of the fingers, wrists, lateral aspect of the feet, and periumbilical area.  Her husband has similar lesions on the same body parts and also over the shaft of his penis.  The remainder of her examination is within normal limits.  
Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: This patient's presentation suggests scabies due to infestation by the Sarcoptes scabiei mite, which burrows into the skin and spreads through direct person-to-person contact. Scabies usually presents with an intensely pruritic rash (often worse at night) in the flexor surfaces of the wrist, lateral surfaces of the fingers, and the finger webs. The rash is due to a delayed type IV hypersensitivity reaction to the mite (feces and ova included). Scabies can also involve other parts of the body (eg, elbows, axillary folds, nipples and areola in women, scrotum and penis in men), but it is uncommon at the back and head (except in children). Examination usually shows excoriations with small, crusted, red papules scattered around the region, often with linear burrows. Patients can also develop small vesicles, pustules, wheals, and excoriations that can obscure the classic burrows in the skin. Diagnosis is confirmed by skin scrapings from lesions revealing mites, ova, and feces under light microscopy. (Choice A) Direct fluorescent antibody testing for varicella zoster can confirm the diagnosis of shingles, which usually presents as erythematous papules progressing to grouped vesicles in a dermatomal distribution. This patient's widespread involvement is not consistent with shingles. shingles (Choice B) Patch testing tests for various common allergens and can help differentiate between allergic and irritant contact dermatitis. Contact dermatitis usually presents as an intensely pruritic and erythematous rash with indistinct margins and is associated with a history of skin exposure to an irritant or allergic substance. allergic irritant contact dermatitis (Choice C) Potassium hydroxide staining of a skin sample can diagnose tinea infections by showing the characteristic segmented hyphae and arthrospores. Tinea infections usually present as pruritic, erythematous, circular, and scaly lesions with central clearing. tinea (Choice D) Punch biopsy is usually indicated for excluding suspected malignancy or bullous disorders, or in situations where multiple etiologies may be possible. However, this patient's presentation is more suggestive of scabies; a punch biopsy would be needed only if the skin scrapings do not confirm the diagnosis. Educational objective: Scabies is a highly contagious disease caused by mite infestation that presents with an intensely pruritic rash in the flexor surfaces of the wrist, lateral surfaces of the fingers, and the finger webs. Patients usually have excoriations with small, crusted, red papules and linear burrows. Diagnosis is confirmed by skin scrapings revealing mites, ova, and feces under light microscopy. References: Scabies (http://www.ncbi.nlm.nih.gov/pubmed/19580575)

A 65-Year-Old Woman Comes to the Physician with a 5-Day