A 38-year-old man presents with a 5-year history of erythematous plaques with silvery scales over extensor surfaces of elbows and knees. Nail pitting and onycholysis are noted. Which of the following is NOT a recognized clinical feature of plaque psoriasis?

Question

Accepted Answer

A. Hyperhidrosis and foul-smelling sweat in lesional areas. ## Recognized Clinical Features of Plaque Psoriasis

**Key Point:** Plaque psoriasis is characterized by well-demarcated erythematous plaques with silvery-white scale, typically on extensor surfaces and scalp. Multiple clinical signs aid diagnosis.

### Correct Features (Options 0, 1, 3)

| Sign | Description | Mechanism |
|------|-------------|----------|
| **Auspitz sign** | Pinpoint bleeding when scale is scraped off | Thinning of suprapapillary epidermis; dilated capillaries in dermal papillae |
| **Koebner phenomenon** | New psoriatic lesions at sites of trauma (scratching, cuts, surgery) | Isomorphic response; occurs in ~25% of patients |
| **Woronoff ring** | Pale/blanched halo around active psoriatic plaques | Vasoconstrictive response at lesion periphery |

**High-Yield:** These three signs are pathognomonic features tested frequently in NEET PG and are essential for clinical diagnosis.

### Why Hyperhidrosis Is NOT a Feature

**Clinical Pearl:** Hyperhidrosis (excessive sweating) and foul-smelling sweat are NOT characteristic of plaque psoriasis itself. While secondary bacterial colonization (e.g., *Staphylococcus aureus*) can occur in psoriatic plaques due to impaired barrier function, this does not cause primary hyperhidrosis or characteristic foul odor as an intrinsic feature of the disease.

**Warning:** Do not confuse psoriasis with other conditions:
- ~~Tinea corporis~~ (fungal infection; KOH mount positive)
- ~~Seborrheic dermatitis~~ (less well-demarcated; flexural distribution)
- ~~Lichen planus~~ (violaceous, wickham striae)

Hyperhidrosis is seen in conditions like hyperthyroidism, lymphoma, and tuberculosis — not in uncomplicated plaque psoriasis.

**Mnemonic:** **AKW** = **A**uspitz, **K**oebner, **W**oronoff — the three cardinal signs of plaque psoriasis.

### Associated Features in This Case

- **Nail involvement:** Pitting (most common), onycholysis, subungual hyperkeratosis, nail dystrophy → suggests psoriatic arthropathy risk
- **Distribution:** Extensor surfaces (elbows, knees, shins), scalp, nails, genitals
- **Chronicity:** Chronic relapsing course; 5-year history is typical

Answer

B. Auspitz sign (pinpoint bleeding on removal of scale)

Answer

C. Koebner phenomenon (lesions appearing at sites of trauma)

Answer

D. Woronoff ring (pale halo around active lesions)

A 38-year-old man presents with a 5-year history of erythematous plaques with silvery scales over extensor surfaces of elbows and knees. Nail pitting and onycholysis are noted. Which of the following is NOT a recognized clinical feature of plaque psoriasis?

Explanation

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