The clinical image shows a chronic inflammatory condition affecting the posterior scalp and nuchal region. Which of the following is a common associated finding in patients with this condition?

Explanation

## Image Findings * **Multiple firm papules and nodules:** Located on the posterior scalp and nuchal region, extending into the hairline. * **Follicular involvement:** Many lesions appear to be centered around hair follicles. * **Coalescence:** Some papules and nodules have coalesced to form larger, irregular plaques. * **Scarring and hypopigmentation:** Evidence of chronic inflammation with areas of scarring and altered pigmentation. * **Alopecia:** Hair loss is visible within the affected scarred areas. ## Diagnosis **Key Point:** The image displays classic features of **Acne Keloidalis Nuchae (AKN)**, a chronic inflammatory condition of the hair follicles on the posterior scalp and neck. AKN, also known as folliculitis keloidalis nuchae, is characterized by chronic inflammation of the hair follicles, leading to papules, pustules, and eventually keloidal scarring and permanent hair loss (cicatricial alopecia). It is more common in young men with curly hair, particularly those of African descent. The exact etiology is unknown but is thought to involve chronic irritation, ingrown hairs, and a foreign body reaction to hair shaft fragments. ## Differential Diagnosis | Feature | Acne Keloidalis Nuchae (AKN) | Folliculitis Decalvans | Dissecting Cellulitis of the Scalp | Tinea Capitis (Inflammatory) | | :------------------ | :--------------------------------------------------------- | :------------------------------------------------------- | :------------------------------------------------------- | :------------------------------------------------------- | | **Location** | Posterior scalp, nuchal region | Vertex, crown, occiput | Vertex, occiput, diffuse | Any scalp area | | **Primary Lesions** | Firm papules, nodules, keloidal scars | Pustules, erosions, crusts, tufted hairs | Boggy nodules, interconnected sinuses, purulent discharge | Erythematous, scaly patches, pustules, kerion | | **Scarring** | Prominent keloidal scarring, cicatricial alopecia | Cicatricial alopecia | Extensive scarring, sinus tracts | Variable, can cause scarring alopecia (kerion) | | **Associated Lymph**| Reactive cervical lymphadenopathy (if severe/infected) | May have reactive lymphadenopathy | May have reactive lymphadenopathy | Reactive lymphadenopathy (especially with kerion) | | **Hair** | Permanent hair loss in affected areas | Tufted hairs (multiple hairs emerging from one follicle) | Permanent hair loss, often with purulent discharge | Broken hairs, black dots, scaling, sometimes kerion | ## Clinical Relevance **Clinical Pearl:** While AKN is primarily a dermatological condition, the chronic inflammation and potential for secondary bacterial infection can lead to **reactive cervical lymphadenopathy**. This indicates the body's immune response to the localized inflammation or infection. ## High-Yield for NEET PG **High-Yield:** Acne Keloidalis Nuchae is a common cause of cicatricial alopecia in men, particularly those with curly hair. Reactive cervical lymphadenopathy is an important associated finding to look for during physical examination, especially in severe or secondarily infected cases. **Key Point:** The characteristic "cobblestone" appearance due to coalescing keloidal papules and plaques on the nuchal scalp is pathognomonic for AKN. ## Common Traps **Warning:** Do not confuse reactive cervical lymphadenopathy with generalized lymphadenopathy. Reactive lymphadenopathy in AKN is typically localized to the cervical region, reflecting a response to the local inflammatory process, rather than a systemic disease. ## Reference [cite: Bolognia, Jean L., et al. Dermatology. 4th ed., Elsevier, 2018, Ch 71, p. 1205-1206]