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D

Darier Disease / Keratosis Follicularis

Etiology: mutation of ATP2A2 gene
Inheritance: AD
Appearance: scaly crusted papules and greasy plaque; alternating red + white nail beds with V-shaped nicking
Location: seborrheic dermatitis distribution (oily areas of the body like chest, back, scalp margins, forehead, nasolabial folds, eyebrows, beard) and skin folds
At risk: adolescents 
Tx: moisturizers, topical retinoids, sun protection​

Dermatitis Herpetiformis

Etiology: cross-reactivity between anti-gliadin IgA antibodies + transglutaminase at the dermal basement membrane
Appearance: papulovesicles or excoriated papules on erythematous base
Location: elbows, dorsal forearms, knees, scalp, buttocks
Sx: intense itching 
At risk: pts with Celiac Disease, Irish or Swedish patients
Associated with: maltomas
Tx: gluten free diet, dapsone 

Dermatofibroma

Etiology: trauma (mosquito bite, shaving nick)
Appearance: tan to pink, firm, hyperpigmented dome-shaped papules with peripheral rim of darkening pigment
Location: extremities
Prog: once you get one, you're at risk of getting more
Dermoscopy: peripheral fine network, central white or pink scar-like area, ring-like globules, dotted vessels
At risk: adults 
Test: "dimple or pinch" sign
Tx: reassurance
 

Dermatofibrosarcoma protuberans

Etiology: rare type of skin cancer characterized by its slow-growing, locally aggressive nature; unknown cause, but an injury is a predisposing factor
Appearance: skin colored, pink or brown irregular border multi nodular fungating mass
Histo: storiform spindle cells very deep with fat getting trapped in it
Sx: painless plaque +/- nodules that feels rubbery or firm to touch
At risk: adults between 20- 60 yo
Location: trunk
Tx: MOHs favored over wide excision; imatinib if t17;22 

Dermatographia

Etiology: skin trauma may release an antigen that reacts with the membrane bound IgE on mast cells triggering histamine release
Appearance: linear wheals + a surrounding erythematous flare which appears 1-3 minutes after stroking + resolves in 30-60 minutes
At risk: young adults
Tx: loose fitting clothes, avoid triggers, antihistamines, phototherapy, omalizumab

Dermatomyositis

Etiology: unknown; classic model considers DM to be the result of a humoral attack against the endothelium of muscle capillaries + small arterioles; risk factors include underlying malignancy + family hx of autoimmune disease

At risk: 30-50 yo, females

Sx: rash appears weeks to months before proximal muscle weakness

Locations:

  • extensor surfaces of MCP + IP = Gottron papules

  • upper eyelids = Heliotrope 

  • malar-like rash

  • chest = V neck sign = Poikiloderma

  • upper back = Shawl sign

  • lateral thigh = Holster sign

Ass. conditions: adenocarcinomas​

Tx: systemic CS

Dermatophytosis / Tinea / Ringworm

Etiology: Trichophyton, Epidermophyton, Microsporum

Appearance: annular erythematous plaque with central clearing and raised scaly edge

Sx: itchiness

Locations:​

  • tinea barbae = beard

  • tinea capitis = head

  • tinea corporas = body

  • tinea cruris = groin

  • tinia unguium = nails

  • ​tinea pedis = foot

At risk: hot humid climates

Tx: topical antifungals (imidazole, terbinafine) unless if it is on head or nails (oral instead: itraconazole, itraconazole)​

tinea capitis
tinea capitis
tinea capitis
tinea capitis
tinea capitis
tinea corporis
tinea corporis
tinea corporis
tinea corporis
tinea corporis
tinea corporis
tinea cruris
tinea cruris
tinea cruris
tinea barbae
tinea barbae
tinea barbae
tinea barbae
onychomycosis
onychomycosis
tinea pedis
tinea pedis
tinea pedis
tinea pedis

Dermatosis Papulosa Nigra

Etiology: activating mutation in FGFR3
Appearance: 1-5 mm in diameter, hyperpigmented brown-black sessile to filiform, smooth surfaced papules
Location: cheeks, temples
At risk: Fitzpatrick types 4/5/6, females
Tx: EDC (for darker skin), cryo (for lighter skin), Nd:YAG laser

Diffuse Palmoplantar Keratoderma (DPK)

Etiology: genetic abnormality
Inheritance: AR or AD
Appearance: hyperkeratosis with white/yellow hue
Sx: hyperhidrosis
Location: symmetric palmar + plantar surfaces
Tx: emollients, keratolytic agents (salicylic acid, propylene glycol), topical retinoids, oral retinoids (acitretin), topical vitamin D (calcipotriol)

Disseminated Superficial Actinic Porokeratosis (DSAP)

Etiology: mutation in: MVD, MVK, FDPS, PMVK or SART3 genes; results in decreased cholesterol in the affected areas of the skin
Inheritance: AD
At risk: European, females
Locations: arms, legs
Appearance: irregular annular plaque with elevated horny rim
Prog: <10% turn into SCC
Tx: compounded off-label topical 2% lovastatin +/- topical cholesterol, sun protection education

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)

Etiology: delayed type IV HS reaction to certain medication (anti epileptics, allopurinol, sulfonamides, minocycline, HIV meds)
Appearance: facial edema, diffuse erythematous macules + plaques that typically occur in 3rd week after starting a med or increasing dose
Ass. sx: high fever, lymphadenopathy, hematological abnormalities, hepatitis, nephritis, carditis, other organ involvement, facial swelling 
Location: first involves face, upper trunk, UE, and then spreads to LE
Tx: stop all suspect medications, systemic CCS, cyclosporin, IVIG

Dyshidrotic Eczema

Etiology: unknown
Location: palms, fingers, soles of feet
Sx: extremely itchy chronic, recurrent
Appearance: recurrent fluid-filled vesicles that resolve after several weeks with scaling
Tx: clobetasol + tacrolimus; severe = Dupixent

Dyskeratosis Congenita (DC)

Etiology: 14 different genes (DKC1 gene mutations on X chromosome); causing telomere shortening = premature aging
Inheritance: AD or AR
Appearance: lacy reticular hyperpigmentation
Other sx: nail dystrophy, oral leukoplakia, early hair greying, sparse eyelashes, hyderhidrosis
Location: upper chest, neck, nail atrophy, oral leukoplakia
Tx: no cure; tx is aimed at maintaining bone marrow function via oxymetholone as this is the major cause of death

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