255 articles
Erythema induratum of Bazin
Erythema induratum of Bazin (Bazin disease, tuberculosis cutis indurativa) is a tuberculid causing recurrent ulcerating nodules on women's calves, linked to Mycobacterium tuberculosis hypersensitivity.
Erythema marginatum
Erythema marginatum is an evanescent, non-pruritic, serpiginous pink rash of the trunk and proximal limbs, a rare but major Jones criterion of acute rheumatic fever and a prodromal sign of hereditary angioedema.
Erythema multiforme
Erythema multiforme (EM) is an immune-mediated, self-limiting mucocutaneous rash with target lesions, usually triggered by herpes simplex virus type 1; distinct from Stevens-Johnson syndrome and toxic epidermal necrolysis.
Erythema multiforme major
Erythema multiforme major (EM majus, erythema exsudativum multiforme majus) is erythema multiforme with mucosal involvement at two or more sites, mainly herpes-triggered, self-limiting, and distinct from Stevens-Johnson syndrome.
Erythema nodosum
Erythema nodosum (EN), the most common panniculitis, causes tender red nodules on the shins, mainly in women aged 25–40, triggered by streptococcal infection, sarcoidosis, IBD, drugs, or pregnancy, resolving in 2–8 weeks.
Erythematotelangiectatic rosacea
Erythematotelangiectatic rosacea (ETR), formerly NRS Subtype 1 and ICD-11 ED90.00, is the flushing and persistent facial redness presentation of rosacea, treated with brimonidine, oxymetazoline, laser, and IPL.
Erythrodermic psoriasis
Erythrodermic psoriasis is a rare, severe variant of psoriasis in which redness and scaling cover 75% or more of the body, causing systemic illness and a dermatologic emergency.
Familial Chilblain lupus
Familial chilblain lupus (FCL, OMIM 610448, 614415) is a rare autosomal dominant monogenic cutaneous lupus with cold-induced acral lesions from childhood, caused by TREX1, SAMHD1, or STING mutations.
Familial cold urticaria
Familial cold urticaria (FCAS, familial cold autoinflammatory syndrome, FCU) is the mildest CAPS subtype: an autosomal dominant NLRP3 disorder causing cold-triggered rash, fever, and arthralgia, with a negative ice cube test.
Folliculitis
Folliculitis is inflammation of hair follicles from infection (Staphylococcus aureus, Pseudomonas), Malassezia yeast, irritation, or drugs, causing itchy or painful pustules; treatment depends on cause, with weak antibiotic trial evidence.
Foot odor
Foot odor (bromodosis) is body odor from bacteria metabolizing sweat on the feet, chiefly isovaleric acid from leucine degraded by Staphylococcus epidermidis; hyperhidrosis, fungi, and pitted keratolysis worsen it.
Generalized pustular psoriasis
Generalized pustular psoriasis (GPP), also called von Zumbusch psoriasis, is a rare life-threatening neutrophilic skin disease with widespread sterile pustules and systemic symptoms, driven by IL-36 signaling and treated with spesolimab.
Granuloma annulare
Granuloma annulare (GA), or necrobiotic papulosis, is a benign inflammatory skin disease with annular plaques and necrobiotic granulomas. Subtypes include localized, generalized, subcutaneous, and perforating; no FDA-approved treatments exist, though JAK inhibitors show promise.
Granuloma faciale
Granuloma faciale (facial granuloma of Lever, ORPHA:615943) is a rare benign chronic facial dermatosis with reddish-brown plaques, grenz zone histology, and frequent misdiagnosis; treatment is topical steroids or tacrolimus.
Guttate psoriasis
Guttate psoriasis, also called drop-like psoriasis, is a psoriasis variant of small scattered teardrop-shaped scaly papules, often triggered by streptococcal throat infection in children and young adults, clearing in months or progressing to plaque psoriasis.
Hidradenitis suppurativa
Hidradenitis suppurativa (acne inversa) is a chronic inflammatory skin disease causing painful nodules, abscesses, tunnels, and scarring in armpits, groin, and other skin-fold areas, typically starting after puberty, more common in women, and treated with antibiotics, biologics such as adalimumab, and surgery.
Hives
Hives (urticaria): itchy wheals from mast cell histamine release, acute or chronic (over 6 weeks). Treated with second-generation H1-antihistamines up to fourfold, then omalizumab, then ciclosporin.
Hydroa vacciniforme
Hydroa vacciniforme (Bazin's hydroa vacciniforme) is a rare childhood photodermatosis causing vesicles on sun-exposed skin that heal with permanent varioliform scars; severe EBV-associated forms (HVLPD) can progress to lymphoma.
Hygiene hypothesis
Hygiene hypothesis: Strachan's 1989 proposal that reduced early-life microbial exposure impairs immune maturation, raising allergy and autoimmune risk; revised as the old friends and biodiversity hypotheses.
Hyperhidrosis
Hyperhidrosis, also known as excessive sweating, is a condition in which a person sweats more than needed for cooling, either all over or in localized areas.
Hypertrophic lichen planus
Hypertrophic lichen planus (lichen planus verrucous, lichen planus hypertrophicus) is a chronic lichen planus variant with thickened, pruritic, wart-like plaques on the lower legs of adults 50-75, histologically marked by eosinophils and rete-ridge-tip infiltrates, distinguishable from squamous cell carcinoma.
Impetigo
Impetigo (pyoderma) is a contagious superficial bacterial skin infection caused by Staphylococcus aureus, Streptococcus pyogenes, or both, occurring mainly in children aged 2 to 5, with honey-crusted lesions treated by topical or oral antibiotics.
Infantile acne
Infantile acne, also called acne in infants, is acne vulgaris developing after 6 weeks of age, typically 6 weeks to 1 year, affecting under 2% of children, mostly boys, with comedones and inflammatory lesions on the cheeks, scarring risk, and links to severe adolescent acne.
Infantile atopic eczema
Infantile atopic eczema (ICD-11 EA80.0), also called infantile atopic dermatitis, is the birth-to-2-years stage of atopic dermatitis: itchy, dry facial eczema with diaper sparing, the first step of the atopic march.
Infantile papular acrodermatitis
Infantile papular acrodermatitis, or Gianotti-Crosti syndrome (papular acrodermatitis of childhood), is a self-limited symmetric papular rash of children triggered by viral infections such as EBV and formerly hepatitis B, resolving in 2-8 weeks.
Infantile seborrhoeic dermatitis
Infantile seborrhoeic dermatitis (ISD), or cradle cap, is a common, non-itchy, greasy-scaling inflammatory rash of infants, peaking before 3 months, affecting up to 70% of young infants, and resolving spontaneously within months.
Infectious dermatitis
Infectious dermatitis (infective eczematoid dermatitis, ICD-11 EA88.0): acute exudative eczematous eruption around a suppurative infection focus, mainly S. aureus, treated with topical antibiotics and soaks.
Inflammatory dermatoses of the vulva
Inflammatory dermatoses of the vulva: noninfectious inflammatory vulvar skin conditions, chiefly lichen sclerosus, lichen simplex chronicus, eczema, psoriasis, and lichen planus, classified by ISSVD histological reaction patterns and diagnosed by examination and biopsy.
Interstitial granulomatous dermatitis with arthritis
Interstitial granulomatous dermatitis with arthritis (IGDA, Ackerman syndrome), rare granulomatous skin and joint disorder, ORPHA:79099, rope sign, linked to rheumatoid arthritis, lupus, drugs, and malignancy.
Intertrigo
Intertrigo is inflammatory dermatitis of skin folds caused by friction, heat, and moisture, often secondarily infected by Candida; common in obesity and diabetes, with weak treatment evidence.