(BMJ) - A 17 yo girl presents with fever, left sided abdominal pain, no urinary symptoms, WBC of 3.7 x 10^9/L, raised AST of 87 U/L, and negative UA. She developed this rash 24h after starting treatment with piperacillin and tazobactam. What is the diagnosis?
Epstein-Barr virus (EBV) infection
Varicella zoster (chicken pox)
Toxic shock syndrome
Pelvic inflammatory disease
Mediterranean spotted fever
You are correct. The development of a rash in response to a penicillin suggests infectious mononucleosis as a result of Epstein-Barr virus (EBV) infection. EBV commonly occurs in teenagers and may be associated with splenomegaly, elevated hepatic transaminases, lymphocytosis and thrombocytopenia.
(BMJ) - A 70-yo man presented with confusion, tremor, leg cramps 4 months after being bitten by an insect in his suburban backyard. This rash developed then cleared. Exam: MMSE 20/30, tremor. Labs: SIADH, elevated ESR. CT and MRI were normal. What is it?
Tinea corporis
Lyme disease
Pityriasis rosea
Sarcoidosis
Hansen’s disease
You are correct. Erythema migrans is seen in 80% of Lyme cases and usually appears within 1-2 weeks of a tick bite. This patient developed lyme neuroborreliosis, which explained his encephalopathy, radiculitis and SIADH (a rare Lyme complication). He responded well to a 30-day course of IV ceftriaxone.

BMJ 2018;361:k1261
Repeated microtrauma from fore-aft foot movements in ski boots led to subungual hematoma and onycholysis. Three months post ski trip, R hallux toenail turned green, surrounded by paronychia. Similar green coloration is seen on the agar plate. What is it?
Chloronychia (Pseudomonas aeruginosa)
Green heme pigments
Lymphedema discoloration
Tinea unguium fungal infection
Green nail polish
You are correct. P. aeruginosa favors warm, moist environments. The combination of repeated microtrauma causing onycholysis, and perspiration causing a moist environment, makes ski boots a particularly conducive milieu. Treatment involved nail trimming and an oral quinolone.
A 54-yo male presented with a flare of Crohn disease. One week prior, he noted a painful red rash on his face, neck, and shoulders. Exam: tender plaques and pustules with surrounding erythema. Labs: WBC 15 K/uL and elevated CRP. What is it?
Gluten sensitive dermatitis herpetiformis
Pyoderma gangrenosum
Sweet’s syndrome
Flea bite papular urticaria
Erythema nodosum
You are correct. Sweet’s syndrome (acute febrile neutrophilic dermatosis) is typically associated with URI, GI infection, IBD, pregnancy, malignancy, or drugs. It presents w/ painful papules and plaques usually on face/neck/arms. He responded completely within 2 weeks of starting a prednisone taper.