Connective Tissue Disorders
- Autoimmune inflammatory conditions have
- Skin manifestations
- Internal organ involvement
- Positive autoantibodies
Differentiation of Connective Tissue Disorders (Broadly)

Feature | Condition | Notes |
Rash, no bound down skin | LE | ㅤ |
ㅤ | Dermatomyositis | More violaceous rash, muscle symptoms |
No rash, bound down skin | Scleroderma | ㅤ |
Sica symptoms (dry mouth/eyes) | Sjögren Syndrome | ㅤ |
Multiple features | Mixed Connective Tissue Disease (MCTD) | Overlapping syndromes |
- M/c vasculitis a/w CTD
- Small vessel vasculitis
LE (Lupus Erythematosus) Spectrum
Acute Cutaneous LE (ACL)

- Associated with Systemic Lupus Erythematosus
- Photosensitivity
- Middle-aged females
- Malar rash/butterfly rash
- Cheeks
- Sparing nasolabial folds
Chronic Cutaneous LE (Discoid Lupus Erythematosus - DLE)


- Mnemonic: Queens (HCQ → Rx) Cat (Cats tongue sign) → Playing disco (Discoid lesions) → In a carpet (Carpet tack sign)

Discoid lesions
- Central atrophy zone
- Activity zone with perifollicular scaling
- Surrounding hyperpigmentation
- Sunlight exposed areas
Signs:

- Cat's tongue sign
- Carpet tack sign/Tint tack sign
- Can lead to cicatricial alopecia
LE Lab Investigations
- Sensitive
- Positive ANA
- Specific
- Anti-dsDNA > Anti-Smith antibodies (anti-SM antibodies)
Cutaneous LE Treatment
- Sun protection
- Antimalarials (specifically HCQS)
Neonatal LE

- "Raccoon eye" / "eye mask"
- Erythematous, scaly eruption
- Around eyes (periorbital)
- Mnemonic: Neonate → Rossa (Ro, SSA)
- Transplacental transfer of maternal antibodies
- Infants prone to congenital heart block
- Antibody test: Ro antibodies / SSA antibodies positive

DermatoMyositis

A 50-year-old female patient with a known case of ovarian cancer presents with difficulty in activities like climbing stairs, getting up from a chair, combing hair, etc. The following characteristic sign was found on examination. The most probable diagnosis is
Features
- Age Group:
- Bimodal (children, adults)
- Prognosis:
- Good in children
- Skin manifestations + Muscle symptoms (myositis)
- Associated with breast/lung/ovarian cancer
- Muscle Involvement
- Proximal muscles affected
- Difficulty: rising, lifting, removing clothes, stairs
- Mnemonic:
- Got to run (gottrun) for jogging (synthetase 1 / jo1) → with a shawl (shawl sign) and holster (Holster sign) → rash () came → cant run
Heliotrope Rash
- Confluent macular violaceous erythema /Violet/Purplish rash around the upper eyelid of a patient.

Gottron Papules
- Lesion around knuckles
- Erythematous
- violaceous
- raised papules
- Interphalangeal, distal interphalangeal, metacarpophalangeal joints

Gottron's Sign:
- Interphalangeal joint spaces, dorsum of hands
- Feature
- Confluent,
- macular,
- violaceous erythema,
- bilateral
Myositis Presentation
- Symmetrical Proximal muscle weakness seen.
- Mainly hip joint muscle weakness
- difficulty in standing up from a squatting position.
- Distal muscle weakness can be present.



- Nail bed telangiectasia - Cutaneous manifestation.
- Calcinosis cutis
Associated Risks
- There is an increased risk of the development of cancer.
- Ovarian cancer risk is increased.
Work Up
- Serology positive
- Proximal muscle weakness tests:
- CK MM levels - elevated.
- EMG
- MRI
- Myositis-specific antibodies:
- Anti-synthetase / Anti-Jo-1 (specific)
- (If positive → Antisynthetase syndrome)
- ↑↑ risk of development of ILD.
- Specific

- These 3 antibodies are not confirmatory.
- Anti-MDA-5 (melanoma differentiation antigen) antibody present.
- Anti TIF 1 (Transcription inhibitory factor) antibody.
- Anti Mi-2 → Good Prognosis (Mission impossible good movie)
- Anti NXP-2
- A/W cancer
- Mnemonic: Got runnning → muscle pain and thalarrnu → apo MD (MDA 5) My (Mi2) Tiffin (TF1) eduth
- IOC:
- MRI guided muscle biopsy:
- Perifascicular atrophy.
Treatment
- Corticosteroids
- Methotrexate
- HCQS
Scleroderma/Systemic Sclerosis

- Sclerosis: Thickening/binding down of skin

Types
- Limited Cutaneous Systemic Scleroderma:
- Skin below elbow and knee
- Anti-centromere antibody
- Mnemonic: Limited to centre (Anticentromere)
- Diffuse Cutaneous Systemic Scleroderma:
- Proximal body
- Anti-Scl-70 (topoisomerase I)
- anti-RNA polymerase III
- Diffuse sclerosing (Scl 70) reach to top (Topisomerase)
- Anti-fibrillarin / Anti-U3 RNP:
- Prognostic for scleroderma
- → risk of RPGN/ILD/PAH
Note: Localised scleroderma



- Morphea
- Autoimmune connective tissue disorders
- NOT a part of systemic sclerosis
- Involves skin
- Contain collagen
- No visceral organ involvement
Clinical Scenario
- Fibrosis around blood vessels in fingertips:
- Hampers autoregulation of blood supply.
- Raynaud phenomenon.
- Early feature
- A lady in a cold environment:
- Color change in fingertips:
- White (exaggerated vasoconstriction).
- Blue (cyanosis due to less blood supply, increased deoxygenated Hb).
- Red (exaggerated vasodilation).
- Skin Presentation:
- Loss of elasticity
- Leather-like skin (fibrosis under skin).
- Salt and pepper appearance of skin.
- inability to pinch skin
- thickened/bound-down
- Other features:
- Microstomia (fibrosis in mouth, difficulty opening mouth).
- Oesophageal dysmotility (fibrosis in esophagus, causes dysphagia).
- Differentiation from achalasia cardia:
- Achalasia cardia: Loss of inhibitory control, increased LES tone.
- Scleroderma: Fibrosis in LES, relatively lesser tone, causes reflux oesophagitis.
- Lung involvement:
- Interstitial lung disease (fibrosis in lungs).
- Specific for Diffuse
- Pulmonary artery hypertension (PAH):
- Specific for CREST
- Fibrosis in pulmonary artery.
- Loud P2.
- DLCO ↓↓ lesser due to vessel wall fibrosis.
- Scleroderma crisis:
- Progressive ↓↓ kidney size.
- GFR lesser.
- RAAS activated, causing hypertension.
- Hypertensive crisis develops.
- Management: ACE inhibitors (oral).

Nail fold capilloroscopy → Diffuse and crest
Patient Presentation

- Mask-like facies:
- Loss of wrinkling,
- shiny skin,
- restricted mouth opening
- visible incisors
- furrowing along oral commissures
- telangiectasias
- Sclerodactyly:
- Bound-down hand skin, deformities (contractures) in interphalangeal joints

Limited Scleroderma (CREST Mnemonic)
- C: Calcinosis → Calcium deposit in subcutaneous space
- R: Raynaud’s phenomenon:
- DOC: Ca channel blockers like amlodipine
- start with lowest dose to prevent postural hypertension
- E: Esophageal dysmotility (dysphagia).
- S: Sclerodactyly.
- Presence of pitting scars in volar aspect of fingers due to fibrosis.
- T: Telangiectasia.

- Additional:
- Anti-centromere antibody present.




Leading cause of mortality:
- PAH > ILD
- ILD
- Lung transplantation possible
- Severe PAH (up to 60mm)
- requires heart-lung transplantation (difficult)
Nutritional Disorders and Skin
Vitamin A Deficiency
Phrynoderma / follicular hyperkeratosis/ Toad Skin
Without 13-cis retinoic acid:
- Earliest skin manifestation: Dryness
- Caused by Vitamin A or essential fatty acid deficiency.
- Small papillary lesions
- Dry, rough, hyperkeratotic papules
- Small keratin plug is at the tip.
- Near back of elbows, knees, joint areas
- Pathology: Impaired follicular keratinisation (Vit A essential)
Nicotinic Acid (Vitamin B3 / Nicotinamide) Deficiency
Pellagra
- Predisposing population:
- Maize eaters (B6 deficient)
Deficiency Manifestations (Pellagra)
- B3 → 3D
- Diarrhea
- Dementia (also hallucinations)
- Dermatitis (photosensitivity),
- C3/C4 dermatome
NOTE: 4 Ds of Glucogonoma
- Death
- Depression
- Delirium
- Diabetes Mellitus (DM).
- Dermatitis (Necrolytic migratory rash)
- Hyperglycemic cutaneous syndrome/ Necrolytic Erythema Migrans

- Deep Vein Thrombosis (DVT).
- Depression.
"Broad collar" rash (Cassal’s necklace),


- Subacute eczema
- On photoexposed areas (V-area of neck, dorsum of hands)
- Hyperkeratotic, lichenified, eczematous patches
- Neck: Castle's Necklace
Treatment
- High-protein diet
- Niacin or Nicotinamide.
Acrodermatitis Enteropathica






- Autosomal Recessive
- Daily requirement: 5–10 mg/day
Types of Zinc Deficiency
- Congenital:
- Autosomal recessive (Zip4 transporter protein deficiency).
- After 6 months / weaning (maternal milk aids zinc absorption)
- Acquired: Chronic alcoholics
Main Features (DDA Mnemonic)
- Dermatitis
- acral, periorificial
- Presents with extensive inflammatory rashes
- oral cavity,
- genital region.
- Rash distribution:
- Cheeks
- Mouth
- Anal region
- Diarrhoea
- Alopecia
- Mnemonic: Z → vayil kude keri appi pokunnath
Treatment:
- Zinc supplementation
Metabolic Disorders and Skin
Granuloma Annulare
- Granulomatous disorder
- Annular lesions (ring-like)
- Asymptomatic
- Commonly on dorsum of hands and feet
- Associated with diabetes (more common), hypothyroidism
- Appearance: Ring-like structures
- Normal / clear centre
- No scaling or crusting
- Smooth overlying surface
- Raised periphery/ring d/t granulomas

- Biopsy:
- Necrobiotic granulomas
- collagen degeneration
Sarcoidosis
Kveim’s test:
- Skin test
Skin Presentation
- Non-specific features (e.g., Erythema Nodosum)
- Specific skin lesions:
- Red-brown papules with normal surface (no scaling, crust, ulcer)
Lupus Pernio:

- Red papules with normal surface on nose, cheeks (sometimes telangiectasias)
Angiolupoid Sarcoidosis:

- Erythema, telangiectasias limited to specific area
Dermoscopy:
- Apple jelly nodules
Treatment for Skin lesions
- Antimalarials (specifically HCQS)
Histology (Sarcoidosis Granuloma)





- Mnemonic: Saratha (Sarcoidosis) → Naked (Naked) Nun (Non caseating) Showing (Shaumann) Ass (Asteroid body)
Features | Notes |
Non-caseating > Caseating | Surrounded by lymphocytes / giant cells |
Naked granulomas. | Absence of lymphatic collar Sparse perigranuloma infiltrate |
Epithelioid cells: | Contain slipper-shaped nuclei |
Inclusion Body | ㅤ |
↳ Asteroid | • Star shaped • intracellularly (inside giant cells). • Also seen in sporotrichosis ↳ but → extracellular. • Mnemonic: Rose gardener roams outside, so star is outside |
↳ Schauman | • Round bodies → Basophilic calcium concretions • Hypercalcemia |
Paraneoplastic Dermatoses
- Skin manifestations
- Indicate internal malignancy
- Not malignant themselves
Acanthosis Nigricans (AN)

- Misnomer: No acanthosis on biopsy
- Appearance:
- Velvety, hyperpigmented texture
- Typical locations:
- Neck, axilla, groins (skin folds)
Benign AN
- Common in
- obese individuals
- metabolic syndrome,
- insulin resistance, diabetes
- Associated with skin tags
- Mechanism: ↑↑ IGF-1
Malignant AN (Paraneoplastic)
- Rapid onset
- Generalised, all over body
- Bilaterally symmetrical
- May have
- Tripe palms,
- Sign of Leser Trelat
- Associated with
- adenocarcinoma of GI tract
- carcinoma breast
Sign of Leser-Trélat

- Sudden appearance of seborrheic keratosis
- On trunk, face
- Mnemonic: Laser (Leser) adichapo Keratosis (seborrhic keratosis) vannu → cancer ullavarkk (Paraneoplastic)
Migratory Erythemas (Two Paraneoplastic Types)
Erythema Gyratum Repens (EGR)

- Typically on trunk
- "Wood trunk appearance"
- Erythema forms concentric swirls/waves, migrate daily
- Associated with lung cancer
- Mnemonic:
- Gyrate → Rotating → concentric swirls
- Repens → Reap what you sou → (smoking) Lung cancer
Necrolytic Migratory Erythema

- Painful, polycyclic, migratory rash
- Associated with necrolysis
- On trunk, anogenital area
- Associated with glucagon-secreting alpha cell tumour of pancreas (glucagonoma)
Inflammatory Dermatoses
Vasculitis - Henoch-Schönlein Purpura (HSP)




Case Scenario
- A child presents with abdominal pain, hematuria, and palpable purpura over the leg.
- Small vessel vasculitis
- Often preceded by infections/drugs
Diagnostic criteria
- Palpable purpura with presence of 1 or more of:
- Diffuse abdominal pain
- Arthritis or arthralgia
- Any biopsy showing IgA deposition
- Renal involvement
Organs affected (PAARpura):
- P → Purpura (commonly on lower limbs).
- A → Arthralgia.
- A → Abdominal pain.
- Complication - intussusception
- Submucosal hematoma
- Main indication for giving steroid → GI bleed
- R → Renal involvement (e.g., hematuria).
- Kidney is the most common affected organ.
- Glomerulonephritis is seen in 1/3 of patients.
- Proteinuria
- haematuria,
- RBC casts
Biopsy:
- Leukocytoclastic vasculitis with IgA-containing immune complexes


Skin Presentation:
- Palpable purpura (felt)
- Thrombocytopenia is Absent.
- Lower legs and buttocks
- Painful
Treatment:
- Most of the cases are self-limiting.
- if not self-limiting
- DOC: Corticosteroids
- Dapsone
- Colchicine
NOTE:
- Palpable purpura → Vasculitis
- Non palpable purpura → Bleeding, clotting, thrombocytopenia
Neutrophilic Dermatoses
- Show neutrophilia (increased neutrophils in blood/biopsy)
Pyoderma Gangrenosum
- Skin ulcerations
- Associated with systemic disorders:
- Inflammatory Bowel Disease (IBD)
- M/c
- Ulcerative colitis > CD
- Rheumatoid Arthritis
- malignancy
- Diagnosis of exclusion: Negative cultures/autoimmune
- Appearance: Painful ulcers with undermined edges

- Healing: With cribriform scarring

Mnemonic:
- So (Psoriasis) So (Spondylitis) So (Sacroilitis) U (Uveitis)
- UV () Sar () Gange () nodu Sorry (psoriasis) paranju ()
Sweet Syndrome (Acute Febrile Neutrophilic Dermatosis)


- Acute onset
- Febrile (fever)
- Neutrophilia in peripheral blood and biopsy
- Commonly in females
Skin Presentation:
- Sudden appearance of painful erythematous papules and plaques on trunk and limbs
- Lesions show pseudo-vesiculation (due to oedema)
Seen in
- Acute myeloid leukemia
- Most common
- Inflammatory bowel disease
- Solid malignancies
- Genitourinary tract
- Systemic lupus erythematosus
- Drugs
- All-trans-retinoic acid
- Granulocyte colony-stimulating factor (G-CSF)
- Idiopathic Sweet syndrome
- Common in women
- Often follows respiratory tract infection
- Amal () Sleep () cheyyumbo Ultra (ATRA) Sweet moshtich → IBD vann
Treatment:
- Potassium iodide, corticosteroids
Behçet's Disease (Behcet's Syndrome)



- Systemic vasculitis
- Anti alpha enolase Ab
- Pathergy → Pathetic diagnosis → misunderstood young patient with recurrent oral and genital ulcers
- Misunderstood a young as 51 () yr old nolan (Enolase) in bus ()
Triad of Features


- Relapsing uveitis (mainly posterior)
- Recurrent genital ulcers
- Recurrent oral ulcers
Features (Oro-Oculo-Genital Syndrome)
- Most common diagnostic feature:
- Recurrent oral ulceration.
- Painful, like aphthae, recurrent
- Recurrence at least thrice in any 12 months.

- PLUS TWO OF:
- Genital ulcers:
- Female: Vulva ulcer
- Male: Scrotal ulcer
- not penile ulcer as in STDs like H. ducreyi, syphilis
- Eye lesions:
- Anterior uveitis.
- Posterior uveitis.
- Hypopyon
- Retinal vasculitis
- Skin lesions:
- Erythema nodosum
- Pseudofolliculitis or papulopustular lesions, OR
- Acneform nodules in post-adolescent patients not on corticosteroids.
- Positive pathergy test
Other Systemic Involvement:
- Non-erosive, asymmetric oligoarthritis
- Multi-system: Pulmonary, cardiac, GI, neurological
Pathergy Test/ Pathergy phenomenon:
- Positive because it can cause systemic vasculitis
- Not a diagnostic criteria
- Type 4 Hypersensitivity reaction
- Procedure:
- Sterile needle puncture on forearm with hypodermic cutting edge.
- Normal response:
- bleeding, clotting, mark disappears in 2-3 days.
- Behcet’s response:
- After 48 hours, formation of sterile pustule

Complications:
- Pulmonary artery aneurysm possible.
- Rupture: Lethal complication.
- Note: Pulmonary artery not involved in polyarteritis nodosa.
Management:
- Corticosteroids
- Ocular involvement:
- Azathioprine.
Mnemonic:
- Bus on a path → Pathergy test
- Oro occulo genital → On bus
Erythema Nodosum (EN)

- Form of panniculitis (inflammation of skin fat layer)
- Most common panniculitis
- Acute onset, self-limiting course
- Tendency to recur
Causes:
- Multiple.
- Reactive process.
- Sarcoidosis,
- Tuberculosis (important in India),
- Crohn's disease, infections
Presentation:
- Tender, erythematous papules and nodules
- Anterior part of legs
- Overlying surface: Normal (no scaling, crusting, ulcerations)
Differentiation:
- From Erythema Induratum of Bazin (tuberculid):
- EI is on posterior calves with ulceration/crusting
Histopathology:
- Septal panniculitis without vasculitis.
- May see Miescher's radial granulomas.
Treatment:
- Anti-inflammatory agents;
- identify and treat underlying cause
Reactive Arthritis (Reiter's Disease)
Q. A 4-year-old girl presented with pain in the left knee and ankle along with some swelling and restriction of movements. There is a history of fever and blood in stools 4 weeks ago. What is the probable diagnosis?
- HLA Association: HLA-B27 and B51
Definition
- *Joint inflammation caused by sterile inflammation reaction
- following a recent entropathic or urogenital infection**.
Triggered by:
- GI infection,
- non-gonococcal urethritis (sexually acquired reactive arthritis),
- HIV patients
Triad of Features


Mnemonic:
- Cant see
- Conjunctivitis (non-gonococcal, esp. Chlamydia)
- cant pee
- Urethritis
- Circinate Balanitis:
- Superficial erosions on glans/penis
- cant climb a tree
- Polyarthritis:
- >1 month,
- non-suppurative,
- lower limbs (post GI/urethritis infection)
- Keratoderma Blennorrhagicum:
- Hyperkeratotic papules on palms and soles

Treatment
- Physical therapy and rehabilitation.
- NSAIDs.
- Intra-articular steroid injection in severe cases.