Hypersensitivity skin reactions: Clinical (To be retired)


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Hypersensitivity skin reactions: Clinical (To be retired)

Medicine and surgery

Allergy and immunology

Antihistamines for allergies


Cardiology, cardiac surgery and vascular surgery

Coronary artery disease: Clinical (To be retired)

Heart failure: Clinical (To be retired)

Syncope: Clinical (To be retired)

Hypertension: Clinical (To be retired)

Hypercholesterolemia: Clinical (To be retired)

Peripheral vascular disease: Clinical (To be retired)

Leg ulcers: Clinical (To be retired)

Adrenergic antagonists: Alpha blockers

Adrenergic antagonists: Beta blockers

ACE inhibitors, ARBs and direct renin inhibitors

Thiazide and thiazide-like diuretics

Calcium channel blockers

Lipid-lowering medications: Statins

Lipid-lowering medications: Fibrates

Miscellaneous lipid-lowering medications

Antiplatelet medications

Dermatology and plastic surgery

Hypersensitivity skin reactions: Clinical (To be retired)

Eczematous rashes: Clinical (To be retired)

Papulosquamous skin disorders: Clinical (To be retired)

Alopecia: Clinical (To be retired)

Hypopigmentation skin disorders: Clinical (To be retired)

Benign hyperpigmented skin lesions: Clinical (To be retired)

Skin cancer: Clinical (To be retired)

Endocrinology and ENT (Otolaryngology)

Diabetes mellitus: Clinical (To be retired)

Hyperthyroidism: Clinical (To be retired)

Hypothyroidism and thyroiditis: Clinical (To be retired)

Dizziness and vertigo: Clinical (To be retired)

Hyperthyroidism medications

Hypothyroidism medications


Hypoglycemics: Insulin secretagogues

Miscellaneous hypoglycemics

Gastroenterology and general surgery

Gastroesophageal reflux disease (GERD): Clinical (To be retired)

Peptic ulcers and stomach cancer: Clinical (To be retired)

Diarrhea: Clinical (To be retired)

Malabsorption: Clinical (To be retired)

Colorectal cancer: Clinical (To be retired)

Diverticular disease: Clinical (To be retired)

Anal conditions: Clinical (To be retired)

Cirrhosis: Clinical (To be retired)

Breast cancer: Clinical (To be retired)

Laxatives and cathartics


Acid reducing medications

Hematology and oncology

Anemia: Clinical (To be retired)

Anticoagulants: Warfarin

Anticoagulants: Direct factor inhibitors

Antiplatelet medications

Infectious diseases

Pneumonia: Clinical (To be retired)

Urinary tract infections: Clinical (To be retired)

Skin and soft tissue infections: Clinical (To be retired)

Protein synthesis inhibitors: Aminoglycosides

Antimetabolites: Sulfonamides and trimethoprim

Miscellaneous cell wall synthesis inhibitors

Protein synthesis inhibitors: Tetracyclines

Cell wall synthesis inhibitors: Penicillins

Miscellaneous protein synthesis inhibitors

Cell wall synthesis inhibitors: Cephalosporins

DNA synthesis inhibitors: Metronidazole

DNA synthesis inhibitors: Fluoroquinolones

Herpesvirus medications



Miscellaneous antifungal medications

Anti-mite and louse medications

Nephrology and urology

Chronic kidney disease: Clinical (To be retired)

Kidney stones: Clinical (To be retired)

Urinary incontinence: Pathology review

ACE inhibitors, ARBs and direct renin inhibitors

PDE5 inhibitors

Adrenergic antagonists: Alpha blockers

Neurology and neurosurgery

Stroke: Clinical (To be retired)

Lower back pain: Clinical (To be retired)

Headaches: Clinical (To be retired)

Migraine medications

Pulmonology and thoracic surgery

Asthma: Clinical (To be retired)

Chronic obstructive pulmonary disease (COPD): Clinical (To be retired)

Lung cancer: Clinical (To be retired)

Antihistamines for allergies

Bronchodilators: Beta 2-agonists and muscarinic antagonists

Bronchodilators: Leukotriene antagonists and methylxanthines

Pulmonary corticosteroids and mast cell inhibitors

Rheumatology and orthopedic surgery

Joint pain: Clinical (To be retired)

Rheumatoid arthritis: Clinical (To be retired)

Lower back pain: Clinical (To be retired)

Anatomy clinical correlates: Clavicle and shoulder

Anatomy clinical correlates: Arm, elbow and forearm

Anatomy clinical correlates: Wrist and hand

Anatomy clinical correlates: Median, ulnar and radial nerves

Anatomy clinical correlates: Bones, joints and muscles of the back

Anatomy clinical correlates: Hip, gluteal region and thigh

Anatomy clinical correlates: Knee

Anatomy clinical correlates: Leg and ankle

Anatomy clinical correlates: Foot

Acetaminophen (Paracetamol)

Non-steroidal anti-inflammatory drugs


Opioid agonists, mixed agonist-antagonists and partial agonists

Antigout medications

Non-biologic disease modifying anti-rheumatic drugs (DMARDs)

Osteoporosis medications


Hypersensitivity skin reactions: Clinical (To be retired)

USMLE® Step 2 questions

0 / 36 complete


USMLE® Step 2 style questions USMLE

of complete

A 57-year-old man comes to the emergency department for evaluation of a painful skin rash. The patient had a mole removed from the tip of his nose last week. He broke out in a painful facial rash over the weekend and has subsequently been experiencing fevers and chills. Past medical history is notable for poorly controlled type II diabetes mellitus, hypertension, lymphedema, and a left kidney transplant for which he is on tacrolimus. The patient develops hives when he takes penicillin. At arrival, temperature is 38.0°C (100.4°F), pulse is 104/min, respirations are 16/min, and blood pressure is 161/82 mmHg. Physical examination is notable for the following finding:

Image reproduced from Wikimedia Commons  

Which of the following is the most appropriate treatment for this patient’s clinical condition?  


Content Reviewers

Rishi Desai, MD, MPH


Antonella Melani, MD

Evan Debevec-McKenney

Salma Ladhani, MD

Hypersensitivity skin reactions are due to an exaggerated immune system reaction towards an antigen, and some reactions can be life-threatening.

Hypersensitivity skin reactions include urticaria, erythema multiforme, Staphylococcal scalded skin syndrome, drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome, and toxic epidermal necrolysis.

Urticaria, also called hives, are slightly raised, well-defined wheals that are 1 millimeter to 10 centimeters in diameter. They’re usually red, blanch with pressure, are extremely itchy, and can pop up anywhere in the body.

The key feature is that these lesions come and go very rapidly - meaning one might appear on the leg as another disappears from the arm.

The reaction involves the epidermis and dermis layers of the skin, and the whole thing typically resolves within 24 hours.

Typically no treatment is needed, but if the itching is really bad, topical cooling moisturizers or oral second-generation histamine H1 blockers can be used like loratadine, desloratadine, fexofenadine, cetirizine, or levocetirizine. If these don’t work, immunomodulatory agents, like cyclosporine or methotrexate can also be used.

Now, if there’s recurrent urticaria, it’s good to try to identify a trigger, so that it can be avoided.

One way is with in vivo skin prick tests, which is where small drops of up to 40 allergens, like pollens, fungi, animal dander, house dust mites, and various foods, are pricked into the skin on the forearm or upper back.

After that, if there are signs of urticaria within about 20 minutes, that implies that the substance is a trigger.


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