For anyone who may be confused about all those "erythemas" out there, here you go!

Erythema ab igne
Erythema annulare centrifugum
Erythema chronicum migrans
Erythema infectiosum
Erythema marginatum
Erythema multiforme
Erythema nodosum
Erythema toxicum neonatorum

1/

Erythema ab igne:

A dermatosis that results from repeated exposure to heat (fires, heating pads, heating blankets, sometimes laptops)

2/

Erythema annulare centrifugum:

A chronic skin condition thought to be a form of delayed-type hypersensitivity

Can be induced by a variety of potential inciting causes: infections (cutaneous or systemic), malignancies, autoimmune conditions, medications, foods, stress, etc.

3/

Erythema chronicum migrans:

Rash of Lyme in early localized disease

(Many have moved away from including the word "chronicum" because nothing chronic about it!)

4/

Erythema infectiosum:

Fever + facial rash that occurs in children with acute Parvovirus B19 infection (so-called fifth disease)

5/

Erythema marginatum:

Evanescent rash observed in acute rheumatic fever after group A Strep pharyngitis

6/

Erythema multiforme:

Acute systemic rash resulting in classic targetoid lesions

Causes are multiple and include: infections (HSV + Mycoplasma classic), autoimmune conditions, malignancies, idiopathic, and medications

7/

Erythema nodosum:

Tender, reddish-purple nodules classically on the lower extremities

Associated with variety of causes: sarcoidosis (and other autoimmune conditions), infections (streptococcal, endemic mycoses, TB, and others), malignancies, and drugs

8/

Erythema toxicum neonatorum:

Pustular eruption that occurs within the first few days of life in newborns. Classic association is that smear of the pustular material shows numerous eosinophils

Cause is unknown

9/

Thought you all might be interested! Let me know of any that I missed!

@BCM_InternalMed @BCMIDFellowship @sargsyanz @k_vaishnani @rav7ks @transplantID @Cortes_Penfield @EvaAmenta