Differential Diagnosis for Dissiminated Follicular Lesions
The patient presents with a 10-year history of disseminated follicular lesions that appear in crops, affecting most parts of the body, including the trunk, extremities, and palms of both hands. The lesions are scaly, and the primary symptom is itching. Based on these symptoms, the following differential diagnoses are considered:
Single Most Likely Diagnosis
- Psoriasis: This is the most likely diagnosis given the description of scaly plaques, involvement of the palms, and the primary symptom of itching. Psoriasis is a chronic skin condition characterized by rapid skin cell production leading to thick, red, and scaly patches. The appearance of lesions in crops and the long-standing nature of the condition also support this diagnosis.
Other Likely Diagnoses
- Seborrheic Dermatitis: This condition could be considered due to the scaly nature of the lesions and the potential for widespread body involvement. However, seborrheic dermatitis typically has a predilection for areas rich in sebaceous glands, such as the face and scalp, which are not specifically mentioned.
- Pityriasis Rubra Pilaris (PRP): PRP is characterized by small, pointed bumps on the skin, which can coalesce into larger, scaly patches. It often starts on the face or upper body and can spread, involving the palms and soles. The long history and the description of scaly lesions could fit PRP, although the primary symptom of itching is more pronounced in psoriasis.
- Dermatophyte Infections (Tinea Corporis): Fungal infections of the skin can cause scaly, itchy lesions. However, they typically have a more localized distribution unless in cases of widespread infection, which might fit the description given.
Do Not Miss Diagnoses
- Cutaneous T-Cell Lymphoma (CTCL): While less likely, CTCL, including mycosis fungoides and Sézary syndrome, can present with scaly, erythematous patches and plaques that can be widespread. The long-standing nature of the condition and the potential for systemic symptoms make this a diagnosis that should not be missed due to its implications for treatment and prognosis.
- Sarcoidosis: Sarcoidosis can manifest in the skin as plaques or nodules and can be associated with systemic symptoms. Although less common, the widespread nature of the lesions and the long history could warrant consideration of this diagnosis.
Rare Diagnoses
- Keratosis Pilaris: This condition is characterized by small, rough, sandpapery bumps on the skin, often on the arms, legs, buttocks, and cheeks. While it can cause itching and has a widespread distribution, the primary description of scaly plaques and the long-standing nature make it less likely.
- Phrynoderma (Toad Skin): A rare condition characterized by dry, scaling skin that can appear on the arms, legs, and buttocks. It is associated with nutritional deficiencies and environmental factors. The description could fit, but the rarity and specific associations make it a less likely diagnosis without further supporting evidence.